Neptune has been show to have a very close relationship with Noire. It can easily be said that the two of them are best friends despite Noire's "tsundere" tendencies towards her. Neptune is often shown to be extremely friendly with Noire; always teasing her and giving her nicknames like "Lonely Heart Noire". Neptune likes to poke fun at Noire for not really having any friends or tease her by telling Nepgear that she wore her swimsuit inside out when Noire explicitly told her not tell anyone. Despite the apparent friendship between the two there is still a sense of competition (more so from Noire) between them. Due to both goddesses being part of the main cast, they have gone through a lot and became very good friends.
Neptune considers this Noire to be a "psuedo-Noire" and teases her just like the Noire in her dimension. Over the course of their adventures in the Ultra Dimension, the two become good friends, to the point where Noire almost bursts into tears about Neptune potentially leaving for good.
Neptune considers Vert to be one of her good friends. She holds a generally high opinion of the Leanbox goddess and is also very aware of her sometimes cunning ways. She has allowed Vert to take her sister and the other sisters out for cosplay while the goddesses were having a "meeting" which consisted of looking at the sister's cosplay. The two are both interested in games and are more extroverted of the 4 goddesses. Vert has produced Neptune as an idol due to the sole reason of Vert playing a game which Neptune finds to be very much in character. Neptune played along with this as it meant avoiding paperwork while still accomplish her duties as a goddess since idol work would boost her citizen's morale as much as administrative work would keep her country running smoothly. Vert, however does not take kindly to any reference to her age which Neptune joked about playfully once. Neptune noticed the mood change as was quickly dragged to another room by a scary looking Vert. To summarize, Neptune and Vert are good friends who mutually cooperate with each other to complete their antics, though Neptune is much less successful at teasing Vert as opposed to Noire. Due to both goddesses being part of the main cast, they have gone through a lot and became very good friends.
Neptune was excited to see another Vert in the Ultra Dimension but Vert asked Neptune to keep her identity a secret which she did. Neptune is sure Vert was no threat despite her declaration of war, as opposed to the other Ultra Dimension goddesses. Vert also demonstrates her cunning ways. This is demonstrated when the Ultradimension Vert easily gave Nepgear a CPU memory without a fight and Neptune, who was initial skeptical that Vert would have ulterior motives for doing so, realized that she most likely did have some hidden motive behind her actions. Neptune and Vert has fought over Nepgear and Peashy to which Neptune won both in the end. Vert and Neptune have the same idea of what school is, apparently, being late, meeting your good friend and playing hooky much to the annoyance of Broccoli. Throughout the course of the game, Neptune too has befriended Vert who sad as well with the potential thought of Neptune and Nepgear leaving the Ultra Dimension permanently.
Neptune considers Blanc, like the rest of the goddesses, to be a good friend of hers. In Hyperdimension Neptunia Victory, she speaks highly of the Blanc from her own dimension and says that she loves hanging out with her. She even says that Blanc always has a rad insult for all of Neptune's antics which implies she enjoys Blanc's rash behavior at times rather than hate it. Due to both goddesses being part of the main cast, they have gone through a lot and became very good friends.
Neptune and this Blanc are good friends but due to this Blanc sticking more with Plutia, Neptune and this Blanc don't exactly have much to tie the two together. However, the two are close enough for Blanc to also be sad about the thought of Neptune leaving the Ultra Dimension permanently.
Much like her relationship with the Noire of her home dimension, Neptune has a very good relationship with Plutia and the two could even be considered best friends. She and Neptune possess similar personalities to an extent which enables them to get along very well. They are both lazy in similar but more or less different ways, but Neptune's upbeat and active personality completely contrasts Plutia's slow and extremely laid-back one.
Neptune and Peashy are extremely close. Since she practically raised her due to her and the Ultradimension Compa and IF staying in the Planeptune Basilicom during the events of Hyperdimension Neptunia Victory, she considers Peashy to be her daughter in a sense. Neptune and Peashy have very similar personalities, even though Peashy is less intelligent than Neptune, probably due to being younger. Neptune loves Peashy dearly, much as she does her own younger sister and loves playing with her.
While Uzume initially attacked Neptune upon their first encounter, Neptune did not hold any ill will to her and began to help her in her endeavors to try and help the Zero Dimension. Uzume is easily able to figure out Neptune and her thinking, as shown when Neptune offers her a chance to come back to the Hyperdimension when they found a way for Neptune and Nepgear to get home.
Neptune has shown to have a generally stable relationship with Nepgear. With Nepgear being her younger sister, of course she loves her very dearly. However, Neptune can be a bit inconsiderate of her sister's feelings from time to time and also needy due to her laziness. Though when things get serious she can step up the plate and actually act like a big sister if needed. Nepgear tends to get depressed when separated from her sister for too long, as shown in Victory where Neptune had been fine for years but Nepgear started losing it in a few days. People often think Nepgear is the older sister due to how much she has to look after Neptune and how she looks a bit older than Neptune.
Strangely enough, the two sisters are polar opposites in many ways. The most notable is personality, with Neptune being lazy, silly, and stubborn and Nepgear being diligent, hard working, and easily persuaded. Also, under the effects of HDD, Neptune changes drastically in both appearance and personality while Nepgear stays mostly the same.
While Neptune is not seen interacting with Uni that often, it is implied that the two have a generally stable relationship. While they aren't necessarily friends, the two of them do not hold any negative feelings towards each other. The two do get along with each other during a Nepstation segment and Neptune finds her to be less of a "tsundere" than Noire overall.
While Neptune is not seen interacting with Rom that often, it is implied that they have a generally stable relationship. It is also implied that when she goes to visit Blanc in Lowee she serves as a playmate for Rom and Ram. The two had a nice Walletcrusher Nepstation segment advertising Tuffmil.
While Neptune is not seen interacting with Ram that often, it is implied that they have a generally stable relationship. It is also implied that when she goes to visit Blanc in Lowee she serves as a playmate for both Rom and Ram, often falling victim to Ram's pranks. Though, during Victory, Ram does call Neptune a dummy, implying that she may not have such a high opinion about her. The two had a nice Walletcrusher Nepstation segment advertising Tuffmil.
During the post-game story of Re;Birth 3, Ram admits that she had a feeling Neptune would have a good plan. Neptune also told Ram about 5pb. using her teeth to play the guitar. Neptune knows how excite kids for sure and Ram is no exception.
Neptune is very close to Compa and considers her to be one of her best friends. They think on a similar wavelength according to IF which is probably why they get along so well. Neptune loves Compa's cooking, saying she always makes the best meals and she also enjoys using her as a pillow for naps.
Out of the three kids raised in Planeptune's Basilicom, Neptune trusts Compa to not cause as much trouble as IF, or Peashy. Other than that just like the three kids, they all get along with Neptune quite nicely, due to their intelligence being about the same range.
Neptune is very close to IF and considers her to be one of her best friends. Despite Neptune and her goofy ways in contrast to IF's more serious and sarcastic nature, the two manage to get along just fine. However, Neptune will often find herself being chewed out by IF if she is caught slacking on her duties as a CPU.
Neptune finds IF's childish imagination hilarious, when listening to her story, she wrote with Peashy. Neptune also finds it scary that IF can find out secrets about her at such at young age, though it turns out IF was just bluffing. Neptune is then sad that IF would choose to get rid of the Neptune cards to make a strong deck of cards to beat Vert. However, for the sake of IF's happiness, she will accept it. Other than that IF looks up to Neptune when she saved her from Arfoire. Like the three kids in Planeptune's Basilicom, they get along really well with Neptune due to have similar thoughts and intelligence.
As IF grew up, she knows she is more intelligent than Neptune and is rescued by her two more times. The two grew really close due to their mutual hatred of eggplants after one of her kidnapping incidents.
Neptune is not seen interacting with Nisa that often, but from what is seen, the two get along relatively well. To an extent their minds are on the same wavelength when it comes to beating up bad guys, though Neptune wouldn't go as far Nisa does with her superhero antics.
Neptune and Gust worked together to defeat ASIC in the events of Hyperdimension Neptunia mk2. The two have a positive view on each other as a result.
Neptune has never truly been seen talking to 5pb in Hyperdimension Neptunia Re;Birth2. but based on what 5pb. says about her occasionally, it can be inferred that the two of them have a stable and friendly relationship. In Hyperdimension Neptunia Re;Birth3, 5pb. is very glad to see Neptune in the Ultra Dimension as she is a familiar face. Without any familiar face, she regresses to her shy self to which Neptune offers her a place in her party and hopes her popularity will rise again so she can be around people more comfortably. 5pb. has been slightly annoyed by Neptune as she told Ram about her playing guitar with her teeth.
Cave recognizes Neptune in Re;Birth3 but in a way where the two are merely acquainted as opposed to Nepgear's relation to Cave where the two are friends. That being said, Cave is happy to join Neptune's party and does trust Neptune.
Red considers Neptune to be her wifey, while Neptune admits she cannot understand her in Re;Birth3. Red shocks her because of her ability to do anything for her pursuit of her wifeys. However, in Re;Birth2, she replaced Nisa, so Neptune and her were more in line with her in jumping headfirst against enemies.
This dimension's Falcom is not seen interacting with Neptune so much, but like with all of Neptune's friends, they most likely have a positive relationship. The two after all did work together to defeat ASIC.
Neptune found Falcom near Planeptune after a storm capsized her boat and nearly drowned her with a light teleporting her to Planeptune. Without any of her equipment, items or money, Neptune offers this dimension's Falcom a place in her party. Falcom helps out Kid IF and Kid Compa with small errands, that Neptune assigns them of which Neptune is aware of. The two get along nicely.
Neptune and MarvelousAQL are good friends based on what is scene after she is recruited into party in Hyperdimension Neptunia Victory and its remake. Neptune finds her to be cool simply because she's a ninja and has never had a party member like her before. Neptune eventually garnered an interest for musicals due to seeing Marvelous in a musical on TV. She also has an interests in ninja arts and went as far as requesting Marvelous to teach her "ninjer magic" which resulted in accidentally ruining Marvelous' clothes.
Neptune was looking for a party member with a Chuunibyou personality similar to IF. MAGES. then shows up and believes it is fate the two met as she was experimenting on "Dimension Sliding" which allows her to travel between dimensions. She plans to finish her technology for "Dimensional Sliding" so they can all go home. However, for the mean time, she joins Neptune's party.
- Broccoli is from the Ultra Dimension in Hyperdimension Neptunia Victory and the Hyper Dimension in Hyperdimension Neptunia Re;Birth3.
Broccoli and Neptune have no on-screen interaction in Hyperdimension Neptunia Re;Birth2. However, since they were both in that game, in Hyperdimension Neptunia Re;Birth3, Neptune and Broccoli have prior knowledge of each other.
From what is seen with her interactions with Broccoli in Hyperdimension Neptunia Victory and its remake, Neptune thinks Broccoli is absolutely adorable and even goes as far as giving her the nickname "Puchiko", much to Broccoli's displeasure. While Broccoli finds her inability to listen to other people annoying, Neptune still likes her just fine and even takes joy in poking the strange creature she rides on, Gema. Broccoli has attempted to make her learn what school is like, which also fails. Neptune thinks it is all about being late, running into your friends then ditching to play games.
- CyberConnect2 is from the Ultra Dimension in Hyperdimension Neptunia Victory and the Hyper Dimension in Hyperdimension Neptunia Re;Birth3.
When CyberConnect2 first appears in Hyperdimension Neptunia Re;Birth3, Neptune notes they had some off screen bonding time during Hyperdimension Neptunia Re;Birth2 to which CyberConnect2 agrees. Once again Neptune is impressed with her power of positive thinking to quickly adjust to the new dimension. During Kid IF's blackmail to force Neptune into buying her candy or revealing her secrets, CyberConnect2 shows up with a bunch of manga and trades some books with IF. Neptune is impressed she is able to find the time to read despite their adventuring.
Neptune is not seen interacting with CyberConnect2 all that often in Hyperdimension Neptunia Victory, but based on their first interaction, Neptune thinks she's very cool and seems to like her a lot. She also seems to like CyberConnect2's optimism as demonstrated when Neptune apologized for taking her away from her home but CyberConnect2 responded by saying she was happy to be able to explore a new world.
- Tekken is from the Ultra Dimension in Hyperdimension Neptunia Victory and the Hyper Dimension in Hyperdimension Neptunia Re;Birth3.
Despite not being seen interacting at all in Hyperdimension Neptunia Re;Birth2, Tekken is happy to see a familiar face in the Ultra Dimension in Hyperdimension Neptunia Re;Birth3. Neptune mistaken her for "Taken" which annoys Tekken. Neptune apologizes for this and offers her a place in her party. When Tekken's bear friend, Kuma visits the Basilicom, Neptune is shocked and cannot believe that closing the door. Tekken and Kuma then beg to stay, so Neptune reluctantly decides to try to convince Histoire to let Kuma stay. During a sparring match between Nepgear and Tekken, Neptune offers to take Tekken's most powerful punch. Having no effect initially, Neptune is then sent flying a long distance. Nepgear wants to learn the punch from Tekken and two forget about the flying Neptune. The two seem to get along well enough. Neptune does not want to go to the arcade with Tekken seeing how she destroyed an entire gang by "resisting a little" when they were chasing her after she beat them in the game.
All is the same for Tekken in the Ultra Dimension with Tekken in the Hyper Dimension with the exception that they met Neptune for the first time rather than having prior knowledge of each other.
Neptune has a mother-daughter relationship with Histoire. Histoire constantly worries and lectures Neptune about her role as a goddess while Neptune just ignores her and dozes off. Histoire wishes Neptune to take her CPU role more seriously, though it seems that Histoire does trust Neptune to get the work done.
Neptune likes this little Histoire finding her more cute than her actual oracle Histoire. Neptune likes to poke fun a her low processing speed which greatly annoys her. Like the other Histoire, she would really want Neptune to get started in working. However, the two get along well enough even if Neptune does slack off.
Neptune has no notable interactions specifically with any other oracle. However, the two did work together to stop ASIC, so they view each other positively.
Neptune has no notable interactions specifically with any other oracle. However, the two did work together to stop ASIC, so they view each other positively.
Neptune and Chika, in the Leanbox ending, are angry at the amount of time Vert and Nepgear spend with each other and not them. The two also worked together to stop ASIC so they view each other positively
Despite being defeated by the Gold Third and subsequently forced to endure a world where almost no one remembers her, Neptune holds no ill will against the Gold Third. The Gold Third did help Neptune and the other CPUs when they were in a bind with Affimojas and Kurome.
B-Sha took over Planeptune at the Gamindustri Rewrite which did not bother Neptune in the slightest. B-Sha was concerned about Neptune's view on her but Neptune assured her it was fine as long as she explains why she fled from Haneda City, in an earlier mission. B-Sha was afraid of monsters, which Neptune helped B-Sha overcome. As a result, B-Sha feels eternally indebted to Neptune. During the Gamindustri Rewrite, Neptune and B-Sha co-ruled Planeptune. Neptune and B-Sha being child-like naturally get along well and together manage to get no work done much to Histoire's displeasure. The two are great friends.
Neptune and C-Sha have very little interaction but Neptune does wish she came up with "Blanny" as a nickname for Blanc first. The two are allies and party members by the Heart Dimension Arc so the two likely have a positive relationship.
Neptune and S-Sha have very little interaction but have worked together in the Heart Dimension Arc to save Gamindustri. They likely have a positive relationship.
Neptune and K-Sha have very little interaction besides bumping into each other because Neptune was teasing Noire. The two have worked together in the Heart Dimension to save Gamindustri. They likely have a positive relationship.
Neptune, like everyone else treats Linda as an Underling. Neptune constantly defeats her with the party. However, Neptune like the 4 other goddess did once attempt to capture Linda to make her break the tie for the most popular goddess. Linda hates the goddesses, but Neptune does not hate her, nor think highly of her.
In Hyperdimension Neptunia mk2 and its remake, Warechu was also seen as another villain to be defeated. Neptune constantly defeated him with the party. Warechu hates Neptune a lot more than Neptune hates Warechu.
Warechu, despite being a member of the Seven Sages, was largely ignored by the goddess cast until he decided to show off his guts when defending Arfoire. Neptune was impressed and considering letting both of them slide, however with Plutia's insistence, Neptune fought and defeated Warechu. Warechu, unlike his Hyper Dimension counterpart gives up his villainous life, so the two are at least not enemies at the end.
CFW Judge stood guard over the captive goddesses which included Neptune. Neptune does not bare any particular grudge against judge and did assist the party in destroying him.
Trick does not care for Neptune despite her looking reasonable small in her human form. The interaction between the two are enemies of which Trick is destroyed by Neptune and her party.
Neptune and Brave are enemies. Neptune has assisted the party in destroying him.
Magic has once defeated Neptune and captured her along with the other goddesses. Neptune does not like her as she even took Planeptune at one point. In the end, Neptune did win out destroying her and reclaiming her city with the help of the party.
Neptune only knows Arfoire as the Deity of Sin. She treats the Deity of Sin as the final boss, something destined to be defeated and for most endings is not at all threatened by her. The Deity of Sin only sees the CPUs and their candidates as weaklings who will be crushed by her. However in the Conquest ending, Neptune does not even get to see the Deity of Sin as she offers herself as a sacrifice to make sure the cursed sword is strong enough to slay the Deity of Sin.
Neptune's relationship with this alternate dimension villain is a bit strange to say the least. Arfoire, despite having never met her universe's Neptune, has a strong hatred for Neptune even before they meet. This is most likely due to either Neptune defeating Arfoire in the first game or helping Nepgear defeat her in the second game.
It is most likely the former since while Arfoire hates Neptune, she never brings up Nepgear, the one who defeated Arfoire in the true ending of Hyperdimension Neptunia mk2. Strangely, Neptune has little knowledge of Arfoire despite facing off in the past. While it makes sense for Nep not to recognize the villain in her regular form, given she never saw that form in Hyperdimension Neptunia mk2, Neptune never recognizes Arfoire even after she transforms into her boss states, with only Nepgear remembering her as the Deity of Sin.
Even though Arfoire is not the main antagonist in Hyperdimension Neptunia Victory, she still gets her chance to show how much hatred she has for Neptune and her friends. However, Arfoire is primarily interested in Neptune's death as she spends a tiny side portion of the game learning how to combine her magic with eggplants, a weakness that belongs only to Neptune and is pretty much ineffective to anyone else. Strangely enough, even though she fails to beat Neptune, this new found power allows her to prosper as an eggplant farmer, meaning Neptune indirectly helped Arfoire in a way.
Neptune is tired of Arfoire as a boss and mocks her constantly enraging her. The two do not get along as Neptune dislikes the amount of times she shows up and Arfoire cannot stand her teasing. Neptune ends up always beating her like all the other Arfoire's in the other dimensions.
Neptune initially met her dimension's Rei Ryghts after trying to break up her one person protest. Rei Ryghts fears Neptune but Neptune does not mean her any ill will. However due to the final info Neptune gave to IF, Rei is stuck trying to rebuild Planeptune a lot more than normal people. Neptune has inconvenienced her probably unknowingly.
Neptune did not think much of Rei Ryghts until the good/true route was unlocked. In fact, she quite forgot about her. Rei, however was concerned about the fact that another goddess has appeared in the Ultra Dimension. Her concerns were correct as Neptune played an integral role in foiling her plans. That being said, in the end she does not hate Neptune and Neptune holds no ill will against her either. Neptune is happy that her actions led to Neptune coming to the Ultra Dimension in the first place.
Neptune finds Abnes to be the weakest of the Seven Sages and promptly attacks her when they first meet as she insults Neptune. Abnes is impressed with Neptune's strength as a CPU despite Neptune not finding a CPU memory, yet. Additionally, when Neptune finds a CPU memory, she is amazed and disgusted that Neptune and Plutia can spend three years lazing around. Neptune also responds harshly to the accusation, that the CPUs were responsible for kidnapping kids, surprisingly correct blaming it on the Seven Sages which raises Abnes' suspicions of the group.
Neptune finds Copypaste too loud and a threat initially and then over the course of the game, she finds Copypaste too loud and not a threat. Copypaste was eventually rebuilt to service Lowee.
Neptune found this evil business man a threat initially and then a joke in subsequent encounters. This is due to the fact, the creature he uses were called his daughters. A lack of a mother suggested to Neptune that he was a slug of some sort. However the fact that the monsters were once children shocked Neptune, but she was not as angry as the other goddesses were. In the end, she and the goddesses are happy to spare Mister Badd, but did grow increasingly annoyed as Mister Badd continually thought they were going to kill him.
Despite Anonydeath taking and brainwashing Peashy, Neptune does not bare a grudge against him. She treats him as a boss to be defeated then saves him in the good/true ending route.
Neptune finds this floating fairy to be an evil Histoire. Croire dislikes that comparison as she is Croire not some different "Histoire". Croire caused Neptune a lot of trouble with Rei Ryghts. Neptune does not seem to hate her but she does not like her either.
Neptune unknowingly foiled Bamo's initial plan to turn the Hyper Dimension Gamindustri to Sociomobilindustri. Neptune, however lost her game as a result of this deed and that makes Neptune quite mad at Bamo. Neptune has attempted to reason with Bamo, telling him his goal will create a world not worth ruling over, but Bamo did not listen to reason. Additionally Bamo sees Neptune as a tyrannical CPU being able to use an OOPart to have a chance at defeating her. Neptune again, foils Bamo's plan to create Sociomobilindustri in the Ultra Dimension. Afterwards, Neptune is happy to let Bamo off easy, to a southern continient to start her nation. Neptune and Bamo have started of a huge enemies with Neptune hating Bamo more and ended off at least not as enemies, but not friends either.
Neptune also foiled Regu's plan to create Sociomobilindustri, while trying again to reason with Regu. Regu also sees Neptune as a tyrannical CPU and used an OOPart to fight her. Neptune defeats her and again, was happy to let Regu leave to a southern continent to create her nation. Neptune and Regu dislike one another initially but ended up not as friends or enemies.
Kurome was responsible for all of Neptune's troubles in Megadimension VII, even making her fall into a delusional state. However, Neptune once understanding Uzume's memories believes that Kurome's blind hatred for Gamindustri was just a misunderstanding. She is annoyed by the fact Kurome would go to such great lengths to get revenge on the Gamindustri that never actually rejected her. Neptune assists Uzume in the fight against her and beats her like all other bosses in the series.
Neptune and this ninja were enemies in the Gamindustri Rewrite. Neptune actually finds the shy ninja robot a neat new enemy that the series has not dealt with his a villain of his personality yet. She defeats Steamax and the two did work together to save Planeptune though Steamax took advantage of the chaos to steal Neptune's Swirl Console. Neptune did Steamax a huge favor by saving Steamax's best friend, Affimojas from delusionary power. As a result the two are no longer enemies.
Neptune is excited to fight the boss of Secret Organization AffimaX. When faced with taking his life as he is corrupted with delusionary power, Neptune refuses and desires to save him for the "happy ending". As a result, the two are no longer enemies.
Despite, the relatively short amount of time, the two were actually together, they were able to befriend each other. As the two are both Neptune, they think in sync and get along quite well. Neptune encourages her counterpart to embrace her protagonist status as a "Neptune" at one point. Neptune is glad that if she does get older she will have a more endowed body. Meanwhile, the Ultra Dimension Neptune finds her adorable.
Neptune and Umio have worked together to save the Zero Dimension. Umio is grateful for Neptune's efforts for both saving the Zero Dimension and befriending Uzume. Neptune finds his voice nice but his fish appearance weird. Nevertheless, Umio knows he can rely on Neptune to help Uzume and the Zero Dimension. The two have a positive view on each other.
Neptune assisted Chuko in finding the one responsible for stealing from her store and regaining the stolen good. Neptune and Chuko share in interest in retro games so the two get along well.