The interactions between characters are often and usually unique depending on who is involved and who they are talking to. Most characters have a connection of some form with the other but with each being unique with every character. Only the most noticeable relationships will be explained further.
For speculation about romantic relationships between the characters see Relationshipping.
Neptune is a very energetic, kind, and happy girl who tends to get along with most of her friends. Though she can be somewhat ditzy and airheaded whenever she sets her mind on something and often can annoy other people with her childish antics, she truly does mean well and is very good at figuring people out and does whatever she can to help someone when they are in trouble. Blanc mentions that Neptune has a unique talent of being able to break through the barriers of peoples feelings to get through to them, which may explain how she is able to make friends so easily. Even transformed, Neptune puts her friends first before anything else.
Nepgear: Neptune is very caring for her younger sister and while she may act more immature than her at times and even get spoiled by her, Neptune also helps out Nepgear whenever she can. Neptune is also arguably more experienced and wise than her younger sister even though she may not act like it at times, with Neptune often encouraging Nepgear when she feels hesitant, reminding her of the friends she's made and how much she has grown in three years. She even calls Nepgear an "amazing little sister" at one point, suggesting that she thinks Nepgear is a truly incredible person. Later it is revealed in an event that Neptune worries that she isn't being a good role model or big sister for Nepgear after seeing how Noire and Blanc interact with their sisters and resolves to work harder, though Nepgear tell her she loves Neptune the way she is. Neptune has also said in her quotes that she dislikes the idea of Nepgear getting married, and "is banning the idea forever." Neptune refers to Nepgear as "Nep Jr."
Compa: Compa is the first person Neptune meets in Gamindustri in the first game. The two interact very well and Compa is even the first one to help Neptune when she falls from Celestia. Interestingly enough, the first time they meet in both games Compa has been wrapping Neptune in tightly wound bandages. Both Compa and Neptune are very friendly with each other with Compa calling Neptune "Nep-Nep." Both girls are also very alike in personality, being kind but ditzy and unwilling to ignore someone who needs help. The main difference between them is that Neptune is more straightforward while Compa may tend to hesitate and be a little more reserved and shy. Along with IF, Compa is part of the main trio with Neptune in the first game, with Nepgear likely being included in the second.
IF: Neptune is very friendly toward IF despite the sarcasm she often gets from her. Upon their first meeting in the first game, Neptune asks IF to join the party which she accepts (as she only thought it'd be with THAT dungeon, not a permanent thing). She also tells IF that she should not try to leave the party and that they should stick together, which IF eventually realizes herself. Neptune can get somewhat upset with IF at times, but she considers IF her best friend along with Compa. Neptune calls IF "Iffy."
Histoire: Neptune and Histoire get along very well in both games. In the first, Neptune is contacted by Histoire to help her, and Neptune quickly agrees, actually being the first person to believe Histoire. Neptune gives Histoire the nickname, "Histy", and rescues her, the two quickly becoming friends. IF even states that they are like sisters.
The second game also has a similar relationship between the two, although Histoire is a bit more strict and harsh with Neptune when it comes to work, Neptune even saying that Histiore makes her work "sweatshop hours." Neptune deeply cares for Histoire though, quickly asking if she is okay when Planeptune is captured by ASIC. She also has a scene with her after Neptune is rescued by her sister and the others, saying that she is glad to be back and hopes to be able to relax with Histoire once their journey is over.
Compared to her older sister, Nepgear is somewhat more shy and reserved, but only slightly. She is still friendly and far more polite to others than Neptune, who tends to say whatever is on her mind. She is also more sensitive and gets saddened more easily than Neptune, but she regains her confidence rather quickly due to the support of all her friends. When making friends with others Nepgear is patient and polite, waiting for them to open up to her while offering to help in any way she can. She care very deeply for the friends she makes and possibly has an even stronger desire to protect them than Neptune does.
Neptune: Nepgear cares about her sister as much as she cares about her. Surprisingly, Nepgear actually helps Neptune a lot more than a younger sister would help her older one with tasks such as work, food, and even massages. Nepgear spoils Neptune almost as much as Neptune spoils Nepgear and they both enjoy working and playing together. When Neptune is captured, Nepgear eventually gains the confidence to rescue her with the help of her friends and upon rescuing the CPU's, hugs Neptune out of happiness.
Blanc: Nepgear seems to have a lot of respect for Blanc. She even mentions to Rom that she believes she is a smart, amazing, and mysterious person. After rescuing her along with Neptune from the graveyard, she finally manages to convince Blanc to talk to her more and become her friend. She often pokes around Blanc's books and actually manages to convince Blanc to let her keep reading them. She also kept Blanc's books tidy and clean when she was away, which Blanc seems to appreciate.
Compa: Compa helps IF rescue Nepgear from the Gamindustri Graveyard. The two are very friendly toward one another and interact well. Compa refers to Nepgear as "Ge-Ge." In a conversation with Neptune, it is revealed that Compa actually likes Nepgear the most between IF and Neptune, though she promises to keep it a secret with her.
IF: Nepgear and IF get along very well as IF acts like a teacher and mentor towards Nepgear. It is thanks to IF that Nepgear regains her confidence after being rescued and is able to use the her HDD form. It also seems that Nepgear and IF both enjoy using cell phones.
Uni: When Nepgear and Uni first meet, they act very friendly toward one another until discovering Nepgear is a CPU candidate, Uni gets mad at Nepgear for leaving Noire behind and leaves, but Nepgear still sees Uni as a friend. She continues to do so despite Uni not completely opening up to her, and even accepts her challenge upon their next meeting. After facing against CFW Brave, Nepgear offers to help and they both defeat him. Uni then accepts Nepgear as a friend and joins her party. The two can pretty much be seen as best friends and rivals to each other as Uni still stays somewhat competitive with Nepgear, but also hangs out with her quite often, enjoying their time together. Nepgear sees Uni as her best friend, reacting with great joy after Uni asks to join the party.
Rom: Rom originally believes Nepgear to be her enemy along with Ram, but after meeting Nepgear while looking for her missing pen, she begins to see her differently. Nepgear manages to convince Rom that she is there to help her sister Blanc and offers to help look for her pen, which they find. After this, Rom begins to really like Nepgear and seems to act like a younger sister to her. Nepgear looks out for Rom and tries to cheer her up whenever she starts to cry. Interestingly enough, the two both seem to have as much desire to protect each other as seen during their fights against CFW Trick.
Ram: Ram is initially jealous and angry with Nepgear, especially after Rom begins to like her. Rom eventually manages to get Ram to help Nepgear though Ram is is still jealous of how well the two get along with each other. After talking to Blanc and Mina however, she decides that she does like both of them and gets along with them from that point on. Nepgear holds nothing against Ram and likes her just as much as Rom despite her jealousy.
Falcom: Both are on very friendly terms with each other after Falcom joins Nepgear's party. Nepgear seems to respect Falcom for her skills as an adventurer, and Falcom seems to respect Nepgear's skills as a CPU candidate. They both enjoy going fishing together, though at first Falcom gets somewhat frustrated when Nepgear catches more fish than she does. Nepgear also enjoys reading Falcom's books along with Blanc. They even spar together at one point, though after getting her shirt cut a bit Nepgear wishes not to do so anymore.
Cave: Nepgear has a large amount of respect for Cave. She seems to be the closest to her after 5pb, offering her advice and being open with her, although doing so unbeknownst to her can cause Cave some discomfort. Nepgear has even managed to get Cave to be more playful by starting a splash fight with her. Nepgear has also admitted that she believes Cave can be cute as well as mature.
Due to her caring and friendly nature, Compa generally gets along best with the girls. She's best friends with Neptune, IF and Nepgear, though she secretly prefers Nepgear the most of the three. She also shows a bit of admiration for Nisa, due to her fondness for heroines. She also turns to Gust for things like financial advice and alchemy. Compa can be described as the sweetheart of the group.
Neptune: Compa is the one to treat Neptune's wounds after she gets injured in both the first and the second game. In the first, she finds Neptune after she is exiled from Celestia and offers to help her rescue Histiore after hearing Neptune explain what she heard in her dream. In the second game, she is still very close with Neptune and constantly keeps wishing to see her until her rescue. In both games the two girls seem to have the most in common, with both of them being kind hearted and a little ditzy. Compa chooses to call Neptune "Nep-Nep" since she seems to have trouble pronouncing her name upon Neptune's suggestion.
Nepgear: Nepgear and Compa both get along in Mk-II. Compa acts like a caretaker for Nepgear, being more sensitive to her more shy personality in comparison to her older sister. Compa also seems to be somewhat jealous when people get close to Nepgear, even admitting this to IF when she gives Nepgear her power up to activate HDD. During a conversation with Neptune, Nepgear, and IF, Compa admits to Neptune that she likes Nepgear most of all three of the group, though she asks to keep it a secret, which Neptune agrees to do.
IF: Though IF and Compa interact well enough in the first game, the second develops their relationship even more. They are childhood friends in Mk-II and they both really enjoy the others company. Compa also seems to know and understand IF a lot more because of this and she even has a rather humorous scene when everyone is arguing and wants Compa to marry them because of her good cooking skills. IF then suddenly yells that Compa is hers. Much to her embarrassment, though surprisingly, Compa is rather happy about hearing that. Compa also calls IF "Iffy" like Neptune does.
Gust: Compa is very friendly to Gust in both games and sees her as cute, smart, and very hard working. Surprisingly, Compa is also the only one Gust hasn't involved in her money making schemes, possibly because Compa flatters her so much.
IF's relationships generally aren't as straight-forward as the others. For Neptune and Compa, she constantly finds herself frustrated by their actions and thoughts, but she does genuinely care about them and even calls Compa her best friend in Mk-II. She's a rather open fangirl of 5pb and gets along well with her. As for Red, she mostly starts off tolerating her, but seems to genuinely care of her as well later on, growing flustered when she thinks Red married Lady Green Heart. Speaking of Green Heart, as she is her goddess of choice, IF is very respectful of her and treats her properly. The rest of the goddesses, she doesn't seem to think any more or less of aside from Neptune.
Neptune: IF sees Neptune as a friend, but she often can get annoyed by Neptune's personality. Despite this though, she shows deep concern for Neptune whenever she gets into trouble such as when she gets poisoned in the first game, or goes missing for three years in the second. IF also seems to blame herself for not being strong enough to help Neptune when she gets captured which makes her determined to get stronger and keep her younger sister Nepgear safe. When Neptune is rescued, IF hesitates to talk to her and apologize, but Neptune eventually goes to see her and tells her not to worry about it.
Nepgear: IF is very protective of Nepgear and serves as a teacher for her upon her rescue. She saves Nepgear from being killed by Underling in their first fight and lends her power to Nepgear so that she can activate HDD again. She can be rather strict with Nepgear at times whenever she gets depressed, but she means well and even admits to Nepgear of how bad she felt for not being able to save her sister. She and Nepgear both seem to enjoy using cell phones. IF also calls Nepgear "Ge-Ge" like Compa when she becomes emotional over her cell phone breaking. IF mostly called Nepgear "Gear" than "Ge-Ge".
Compa: In the first game, Compa and IF are merely friends with each other along with Neptune, however in the second, they are childhood best friends. IF may have feelings for Compa as evidenced by her extra voice clips, and scenes where Nepgear's party talks about having Compa cook for them as their wife, and Nepgear asking whether Compa likes Neptune or IF more. IF reacts strongly and embarrassingly in both situations. Compa knows how IF gets sad whenever she loses or breaks a cell phone and takes her to the repair shop to get it fixed.
Vert: In the first game, IF is secretly a follower of Lady Green Heart despite not being born in her land. When they first meet, IF is flustered and especially embarrassed when Green Heart uses her nickname that Neptune gave her, "Iffy." Aside from the first interaction though, she treats her like any other person she wants to be friendly with, addressing her problems and supporting her to make the right decisions along with Neptune and Compa.
Due to her aggressive nature, Blanc has the roughest relationships of the cast. She generally doesn't like any of the other goddesses, due to their ongoing rivalry, and doesn't relate well to either IF or Compa due to associating with Neptune. However, she does get along well with the other party members. She shares her books with Nisa and Red, 5pb thinks of her like a cute little sister and she invites Gust to move to Lowee after their journey is finished. Histoire also mentions that despite Blanc's indifferent attitude, she truly cares about others more than any other goddess, which suggests that she might hide her true feelings under her more aggressive nature.
Neptune: Blanc seems to have a jealous attitude towards Neptune. According to Histoire, this is because Neptune has an open personality, a cute smile, bigger breasts, and yet she is also respects Neptune despite this. While Neptune tries to act friendly toward Blanc, she usually just acts annoyed with her actions and tries to deny any relationship with her. However, Blanc also respects the fact the Neptune is always herself and is able to get through to other people easily despite how they act towards her. The relationship seems to come off as a love-hate sort of thing in this regard, though Neptune seems to be oblivious to this, seeing Blanc as a friend regardless of her attitude. In the manga, the two are on much better terms and are good friends. They often are the two that cause mayhem.
Nepgear: Blanc likes Nepgear far more than Neptune. The two get along well and Blanc even offers to be Nepgear's friend after being rescued. She states that Nepgear doesn't have the ability to break through emotional barriers like her sister and she prefers her this way. She is also impressed by Nepgear's ability to keep things tidy and lets her read her written books. She even considers hiring Nepgear as her personal librarian once the adventure is over.
Rom and Ram: Blanc has a very deep relationship with her younger sisters. Often times, the two are getting into trouble and purposefully trying to make Blanc angry simply because they enjoy it. Blanc is very annoyed with their antics most of the time though Mina attempts to use arguments between them to try and improve Blanc's self control. This could also be the reason Blanc is much more prone to anger in the second game. However, Blanc very deeply cares for her sisters despite how much they annoy her. This is proven when the two team up with Nepgear and her friends and save her from the graveyard. She is grateful for being saved by them, smiles, and apologizes to the crying twins for making them worry about her, possibly even hugging them like Neptune hugged Nepgear.
Falcom: Blanc is a huge fan of Falcom's pseudonym A. Christin, and reads all of her books. When Blanc discovers that Falcom is her favorite author, she immediately becomes giddy and asks for her autograph and becomes very pleased when she gets it. Nepgear remarks that she looks like she is on cloud nine when this happens. Falcom is probably the only person that Blanc has serious respect and happiness being with.
Mina: Blanc often leaves the care of Rom and Ram with Mina, since she is quite capable of taking care of the twins when she is busy. However, even Mina seems to have her limitations as evidenced by the true ending when the twins draw in Blanc's book and Mina apologizes to her for not looking after them. Mina often tries to get Blanc to stay calm whenever she starts to get angry and is successful to a degree in that regard, and she also tries to improve the relationship between the sisters through things such as games and books. Nepgear has said that Mina is the mother while Blanc is the father when it comes to the two twins.
Rom and RamEdit
Rom and Ram are both little girls who are rather mischievous, but also very happy go lucky. While Rom is shy and reserved, she is actually more open than her sister, who can sometimes misjudge people like Nepgear and let her more aggressive emotions get in the way of making friends (especially when it comes to them being friends with Rom). They both enjoy playing with each other and their friends though, and are willing to help out if someone needs it.
Blanc: Rom and Ram love their sister deeply, and Blanc cares for them greatly as well. They love nothing more than to mess with her, even getting happy when she gets mad at them. Blanc even thinks about giving one of the twins to Vert when she gets angry. Despite this, the three sisters share a very close bond.
Nepgear: The twins first meeting with Nepgear is a rather hostile one, as the two believe that Nepgear is only in Lowee to take their shares away. They continue to believe that Nepgear is an "evil goddess" until Nepgear helps Rom find her missing pen, telling her about why she is on the journey she is. This opens up Rom to Nepgear, but Ram still distrusts her despite eventually lending her a hand with Rom when they go to reseal the Killachines released by Underling. When Rom becomes bedridden and brainwashed from lack of shares and the manipulation of CFW Trick, Ram asks Nepgear to help her save Rom, finally trusting Nepgear when she does, at which point both twins join Nepgear's party. Rom gets along especially well with Nepgear after their first friendly meeting, and while Ram still gets jealous of how much they do, she eventually admits that she likes Nepgear too.
Neptune: The twins both find Nepgear's older sister to be rather immature and silly. Rom comments that she is funny and she likes her while Ram thinks she's an even bigger baby than Rom.
Mina: Mina is considered a motherly figure to the two young twins and acts as their caretaker. She cares very much about the twins, but can also be very strict with them. Mina seems to be the only one who can control the twins and their rambunctious behavior, and can sometimes become very scary and quiet them down instantly. Still, she does reward the two for doing a good job when they are being good kids or CPU's and also spoils them by getting them new games and snacks.
Red, for the most part, thinks of the other girls as members or potential members of her lesbian harem, openly referring to them as her wifes. Her interactions with IF are more heartfelt, suggesting she has genuine feelings for her beyond lust. She does seem to get along well with Green Heart, frequently playing games with her and even entering a virtual marriage with her in the Four Goddesses Online game, and she gets along well enough with White Heart for the latter to lend her some books despite Red letting loose a fart in her presence resulting in White Heart chasing her.
Noire has a very peculiar personality, not seeming to care as much about having friends as other people do, though this could just be a cover up giving her the personality of a tsundere. She is polite however, and when she starts to open up to other people, she often asks them for advice and admits other things about herself to them as well. This is evidenced in her meetings with Neptune and Nisa. She is very studious and hardworking, and while she occasionally makes mistakes, she always means well and doesn't ever mean to hurt anybody in the process. She also seems to have a habit of saying the exact opposite of what she means, often using the phrase, "Not like I'm... or anything."
Neptune: Noire and Neptune are rivals and friends with each other. Noire is always trying to best Neptune with her "future-proof" technology and devices and skills in battle. She also seems to believe Neptune to be very irresponsible when it comes to her duties and yet also understanding of how Neptune may prefer to be a human to a goddess at times since she herself sometimes feels the same way. Noire seems mostly confused about what she thinks of Neptune since she understands and knows a lot about her, yet denies wanting to do things for her. By the end of the first game however, it seems like the two are on good terms with one another, and Noire even seems to think of Neptune as a friend in the Manga (Though she kicks her out of the Basilicom after her antics with Blanc against a cockroach.) In the second game Noire seems to consider Neptune her closest friend and seems extremely happy whenever Neptune comes over to visit, but fiercely denies it due to her tsundere nature.
Nepgear: Noire seems to have a respect for Nepgear and is also grateful to her for being Uni's friend. She even admits that she reminds her of when she and Neptune first met, though she asks Nepgear not to mention this. She also seems to approve of the rivalry between Nepgear and Uni.
Uni: Noire has high expectations of her sister and is often encouraging her to try and follow in her footsteps. Despite how critical Noire can be of Uni, even saying that she should have rescued her sooner, she does truly care about Uni and even admits that she has become a much stronger and reliable person during her absence. In the true ending, Noire is surprisingly upstarted by Uni in doing CPU paperwork, becoming discouraged when Uni points out that she accidentally messed up on one of the papers.
Uni is a lot like her older sister in many regards, but is a little more accepting of having friends than her. She mainly tries to get stronger on her own but comes to realize the importance of having others to rely on thanks to Nepgear. She can be a little more short tempered then her sister, but she does truly care about her friends and those close to her despite the fact that she doesn't like to show it.
Nepgear: Uni is very friendly with Nepgear at first until she realizes who she is. After discovering she is a CPU candidate, she gets angry at Nepgear for leaving Noire and the CPU's behind and leaves, though she later thinks she was too hard on her. After running into Nepgear a second time, she tries to apologize, but Nepgear is too focused on getting hematite from a monster which causes Uni to lose her patience. After Nepgear foils a sneak attack by Underling, Uni asks Nepgear to duel her for the hematite she collected. She loses and after leaving, she contemplates on Nepgear is stronger even without her friends despite having so many of them with her. She sees Nepgear one more time in Lastation and Nepgear offers to let her join again, but she refuses since she doesn't want to be a burden to Nepgear, though she does promise to see her again. They meet again in Leanbox and Nepgear asks Uni for help in identifying the authenticity of the oracle of Leanbox, who is really Underling in disguise. After rescuing the mascot and real oracle, Nepgear then asks for help from Uni, Rom, and Ram when a planned concert goes awry, and they succeed. Their next meeting is when Nepgear finds her defeated by Brave the Hard. By this point, Uni is feeling very depressed and thinking that she is useless and that her efforts to become stronger are a waster of time. She even mentions that she failed at life. Nepgear manages to convince her that it is fine to rely on others and to work together to save their sisters when Brave shows up again. The two work together and overcome him and Uni finally asks to join Nepgear's party, which Nepgear happily accepts. From that point on, the two are friends and rival to each other and they get along very well. Uni is very easily happy with Nepgear, though she sees her as a bit of a space-case at times. However when they work together, the can very easily accomplish whatever task they try to do. They hang out together in one scene trying to do things a "normal girl" would, but realize that it isn't really all that fun so they go to an arcade instead.
Rom and Ram: Uni gets along pretty well with Rom and Ram, though she is often mocked by the two for being snooty and short with them at times. During one battle with Trick the Hard, it is shown that she does care about the twins when she threatens to beat them up if they join ASIC. She also joins in on whatever job they and Nepgear are working on even if she doesn't agree with it.
Noire: Uni views her older sister as a role model and strives to surpass her. Because of this, she has a bit of an inferiority complex with her. She wanted to be chosen to go fight ASIC three years ago with the CPU's and Noire, but Nepgear was chosen instead. This is what strove her to start training on her own so that she could defeat the enemy her sister couldn't. She finally saves her with Nepgear and though Noire doesn't get as emotional as the other sisters with Uni, she gives her thanks and tells her that she has grown later in Lastation. This causes Uni to cry in happiness, grateful that her sister is finally praising her for something after working so hard and seeing her as a reliable person. She happily agrees to help her from then on. Uni also shows great concern for her sister after she returns, worried that she may push herself too hard. This is the catalyst for the candidates surprise maid party when Uni mentions this to Nepgear, Rom, and Ram. Later on in the true ending, Uni is working on documents with Noire and even proofreads her older sisters work, pointing out that one of her documents may be misspaced.
Vert's laidback nature is generally an asset, as it generally lets her get along with the girls due to their shared gaming interest, such as playing with Red and 5pb on Four Goddesses Online. Her relations with Nisa and Gust may be a bit strained, seeing as the former wouldn't become a game addict for her guild in exchange for bust size secrets and the latter swindled her twice for money on things she wanted. She also seems the most tolerant of her fellow goddesses, generally not getting involved with them and being the one to attack Neptune the least in the first game. On the same note she also seems to be the most mature of the four and it can be argued that she along with Neptune are the peacemakers of the four. She even admits that she needs to be there for the other three to Nepgear in MKII She shows particular concern with IF and how she thinks of her, implying she might have feelings for her.
Neptune: In the first game, Vert is still quite open and friendly in comparison to the other goddesses, but she still agrees to banish Neptune to the human world. After seeing her again and learning she lost her memory along with the information she gets from Neptune and her party, she agrees to help out the team to uncover a plot by Arfoire in Leanbox. They succeed and eventually Vert is convinced by Neptune to help fight Arfoire in the final battle. She even admits that "Nep-Nep" has become her friend at that point. She is still quite friendly with Neptune in the second game, though she doesn't call her by nickname in that continuity. She does however admit to Nepgear that she worries about her due to her personality and what would happen to her if she didn't have Nepgear as her sister.
Nepgear: Vert is very friendly with Nepgear and even admits that she is jealous of Neptune for having such a good little sister. She is grateful to her for rescuing her from the Graveyard and says that she is welcome to relax there anytime if she gets tired of Neptune.
Chika: Vert's relation with Chika is probably the closest one she has with someone who's not a main character. Chika is heavily implied to have feelings for Vert, but while Vert does care of Chika in her own way, it's not indicated if those feelings are romantic or not. The two are very close regardless, sharing a bed together and giving each other massages.
Due to her shy nature, 5pb is a little more hesitant about getting close to the girls, but she does have some good relationships among them. She and Cave are best friends and compliment each other well. She also is close to IF, due to her helping her open up to people. She seems particularly fond of Black Heart and White Heart, seeming rather giddy about the idea of performing with the former and thinking of the latter as someone she'd like as a little sister when she's not so aggressive. She also seems okay with Green Heart, playing a bit of Four Goddesses Online with her.
Nepgear: 5pb is originally shy around Nepgear as she is with everybody else in mk2, but after Nepgear helps her by saving a concert in Leanbox, she becomes respectful of Nepgear and even offers to join the party afterwards. She also admits that she had become a fan of Nepgear and the CPU candidates ever since Nepgear put on the concert. In this regard, it could be said that Nepgear along with Cave help 5pb to overcome her timidness as Lyrica, similar to how IF did in the first game. It would also seem that 5pb has a crush on Nepgear saying it's always the best feeling when someone you like is listening to your songs after talking about how Nepgear is always listening to her songs. Nepgear asked this about this saying "someone you like or who I like". 5pb instantly became flustered and ran off saying she said something totally embarrassing , possibly letting her feelings slip. She could have just meant this in a close friend matter however, and ran off due to her shy nature.
Cave: Before Nepgear, 5pb was most likely the only person Cave consider a friend. The two have a high amount of respect for one another and are very close. Cave also teases 5pb sometimes, bringing up some of the rockstar's embarrassing moments to light in front of Nepgear.
Vert: 5pb has a high amount of respect for Vert, and even offers to protect her while Vert walks though being assaulted by fans wanting her autograph (much to Vert's jealousy) and offering to wash her back. Vert enjoys her company giving her a voucher code for Four Goddesses Online.
Chika: 5pb seems to be afraid of Chika, due to the Oracle's irritation at Vert being captured. Chika decides to be a little nicer towards 5pb, though she still scares her off and later sending 5pb hate mail telling her to go save Vert if she has time to do a "stupid show".
Like the other girls, Nisa mostly gets along well with the others. She shows concern for Noire and Vert, mostly about the former's sleep habits and the latter's seeming lack of friends. She also is all right with Blanc, with the two of them having beaten up bandits over insulting their chests and Blanc willing to share her books with her. She also seems to be a fan of 5pb, cheering for her at her Leanbox concert. Since she sees herself as an ally and friend to all those who are good and those who defend good, she easily gets along with the CPU's and their friends. However she can also get quite jealous, especially when comparing her flat chest to the CPU's.
Neptune: Nisa and Neptune don't seem to interact much in the first game, Nisa even accidentally kicking Neptune right in the face on their first meeting. They have a much friendlier relationship in the second game, easily on the same page when it comes to punishing evil ones in the name of justice. Nisa even challenges Neptune to a race during the hot spring event.
Nepgear: Nisa joins Nepgear's party after saving them from Underling mainly to be in the same party with a CPU who is trying to stop ASIC for good. She refers to Nepgear as her sidekick and sees herself as the leader of the party. However she gets along quite well with Nepgear despite this and the two seem to care about each other, Nisa often commenting on how great a sidekick Nepgear is. Nepgear also shows concern for Nisa at several points in the game.
Blanc: Nisa has a good relationship with Blanc in the first game. Nisa lies to Blanc about her writing to stay on good terms with her, though she later says she can't believe how bad the writing system of Celestia is. Later when two bandits are being chased by Blanc in her HDD form, Nisa intervenes and tries to stop her, but then joins her when the bandits mock her flat chest much how they did to Blanc. This could show that while both are most of the time willing to do the right thing, they have their limits when it comes to certain things like having their breasts mocked.
Gust: Nisa and Gust have a strange relationship. At first they seem to be on good terms, but then Gust mocks Nisa's chest saying it smaller than a pane of glass. Nisa usually drags Gust along on her adventures annoying Gust greatly.
Like most of the girls, Gust generally gets along well with everyone in the party. She usually gives them helpful financial advice or spending tips, mostly to Compa and her poor spending habits, but she's not above charging them fees for her help, like garnering hush money from Vert to keep quiet about her DVD set or asking Noire for money to make an experimental drink for her voice. She seems to be all right with Blanc, as she considers her offer to move to Lowee after their adventure.
Since Histoire is known as the world's everything, she most likely knows everything about everybody. She especially understands the CPUs and CPU candidates well. She serves as a mentor and guide to the heroes in their quests to fight Arfoire in both games. Her personality in the first game is rather girly and cute, often adding emoticons to the end of her sentences. However in the second game, she acts far more mature and serious, and also appears to be older. In either case though, she does care about the people who she interacts with and wants to help them in any way she can.
Neptune: Neptune is the goddess to respond to Histoire's cry for help in the first game and guides her several times throughout her adventure. The two get along very well and Neptune dubs Histoire "Histy" as a nickname. In the second game, Histoire is a little more strict with Neptune, trying to get her to take her responsibilities as a CPU more seriously. However she also notices that Neptune seems to really spoil and get along with Nepgear a lot and is very happy about her caring about her sister so much.
Nepgear: Histoire care for Nepgear just as much as she care for Neptune. Most times, Histoire worries about Nepgear due to the CPU candidate getting captured before. Histoire tells Nepgear to look at Neptune as a bad example of a CPU. Despite all this, Histoire is like a mother figure to the girls and cares for them greatly
Compa and IF: Histoire is friendly with both Compa and IF in both games and often asks them for help with Neptune and Nepgear in their battles against Arfoire. It is both of them who are requested by Histoire to go and help the CPU's when they are captured. IF also seems to have a job of making sure Neptune doesn't sneak out on work, capturing her and bringing her to Histoire whenever she tries to do so.
Arfoire: As the only other person who knew Arfoire before she turned evil, Histoire is somewhat piteous towards her and sympathizes a little with her original problems. In a letter she sends to 5pb's radio show, she talks about how she would change the past if she could and stop her best friend from making a terrible mistake, implied to be Arfoire.
Mascots: Histoire seems to have a history with the four mascot characters Nepgear and her team recruits to help them rescue their sisters in Mk II. She has two scenes where she speaks with them, voicing her concerns about how she may be making mistakes and her failure to stop ASIC, as well as sending Neptune and the CPU's out on the mission that got them captured and how it could be the same for their sisters. She is reassured by the mascots however, and thanks them. It is unclear how they met, but it appears that they are all close friends and they talk about their past after Histoire has finished talking about her fears, though it is never shown.
Due to her reserved nature, Cave is a bit quieter about how she feels about the other girls. She's the most open about 5pb, as the two of them are best friends and she loves her musical talent.
Chika: Chika is also a close friend of Cave's. Cave knows her well enough to determine when she's just acting and is willing to put her foot down when it interferes with the task at hand.
Falcom is a very friendly character and experienced adventurer who gets along with just about everyone she meets. She has not only many friends, but also many admirers including people who read her books and travel records, along with people who are grateful for being saved by her countless times. She can be somewhat nosy by involving herself in other peoples business, which she herself admits, but she means well and is always willing to lend a helping hand to those who need it.
Nepgear: Falcom and Nepgear have a great friendship with each other. When Falcom first meets Nepgear she is quick to point her in the right direction and she is later helped by Nepgear to save her island from ASIC. Afterwards she offers to return the favor later, which she does when Nepgear offers her to join the party. The two seem to have a small rivalry when it comes to fishing, with Nepgear getting lucky the first time and making Falcom slightly jealous, though it doesn't happen the next time. Falcom also seems to care for Nepgear, offering to inspect if there is a possible wound when Falcom accidentally slashes her clothes.
Blanc: Falcom is honored that the CPU of Lowee is a fan of her written work and happily gives her an autograph. She admits that she is a little embarrassed, but likely gets along with Blanc considering how much she respects Falcom.