Neptune and Plutia are very close friends. Neptune enjoys lazing around and napping with Plutia. Plutia generally follows Neptune's advice since Neptune is a bit quicker when thinking. Plutia feels due to Neptune's ability to make friends, playful and outgoing personality, Plutia, herself was able to make friends. As such, she feels grateful to Neptune. However, like everyone else, Plutia's transformation scares everyone, Neptune included.
Plutia's original best friend is Noire. The two spent a lot of unspecified time together before Neptune came to the Ultra Dimension. During which Noire pushed Plutia to not transform and with some success to run Planeptune. After Neptune arrive, Noire was shortly later able to found her nation and somehow managed to not visit for about three years. When Plutia visited, she was overjoyed though, she tried to hide it. Noire is happy to be around Plutia whenever possible, though she makes up excuses to keep up the air, it is for work. Plutia has once transformed to teach Noire a lesson. Regardless, the two are close friends.
Plutia was excited to see another Noire from the Hyper Dimension but that was about the extent of their interaction. This Noire has not seen Plutia transforms and probably does not think too much about her.
Vert and Plutia seem to have a good relationship, while there is not much to connect the two. Vert fears Plutia's transformation like everyone else. Vert has hosted a Nepstation segment with Plutia, with Plutia trying figure out how much Vert sleeps in a week but ultimately gave up due to her slowness. That being said, she was shocked to see how much Vert cares about her age. Overall the two get along well enough.
This Vert was introduced to Plutia and her transformation in very quick succession. As such, she would rather try to stay away from Plutia due to fear.
Plutia is Blanc's best friend, however it may not work that for Plutia due to Neptune and Noire. However, Blanc was able to make friends due to Plutia and was shortly able to reclaim her nation with Plutia making Neptune and Noire help Blanc as well so she owes a great deal to Plutia. Plutia is very happy to have someone listen to her so quickly which is a result of Blanc fearing her transformation like all the others. Blanc, unlike Noire does not hide the fact she tries to visit Plutia as often as possible. Plutia and Blanc are happy to be friends with each other.
This Blanc was introduced to Plutia and her transformation in very quick succession. As such, she would rather try to stay away from Plutia due to fear.
Plutia considers Peashy to be her daughter as she raised her up in the Basilicom. However, Peashy still prefers her "Neptuna". Peashy refers to Plutia as "Ploot". The two still get along well enough and play around together. Plutia was able to assist in jump starting Peashy's memories with the doll she made for Peashy. Peashy loves the dolls that Plutia makes and two are very close regardless.
Nepgear is happy came to the Ultra Dimension because that means Neptune did not have to leave so soon. Nepgear fears Plutia's transformation but Nepgear is able to read her mood in such that state. Like everyone else in Hyperdimension Neptunia Victory and Hyperdimension Neptunia Re;Birth3, Plutia has mistreated Nepgear, although in Plutia's case, it was intentional to kick-starting Peashy's memories.
Like the other candidates, Uni had only recently met Plutia but the two are friends enough. Like everyone else, they fear Plutia's transformation.
Like the other candidates, Rom had only recently met Plutia but the two are friends enough. Rom, however, thinks Plutia's transformation is not so bad if one gets used to it.
Like the other candidates, Ram had only recently met Plutia but the two are friends enough. Like everyone else, they fear Plutia's transformation.
Plutia also raised IF as a kid and after a traumatizing rescue attempt, IF always refers to Plutia as "Lady Plutia". Plutia perfers a more informal name, but IF refuses. IF fears Plutia and her transformation a lot more, trying to do whatever Plutia asks of her as quickly as possible. Plutia still cares for IF and isn't too sad about how IF is stiff around her. The two are relatively close and Plutia still loves her, even if IF does not feel the same way.
Plutia raised Compa and the two are very close. However, Compa does chastise Plutia because most of the excessive injuries found on the patients the goddesses bring in are caused by Plutia. Plutia, of course feels bad. Plutia likes to use Compa like a pillow similar to Neptune. The two get along very nicely.
This Histoire is Plutia's oracle. Similar to Neptune and her Histoire, this Histoire does attempt to lecture Plutia to make her perform her duties as a goddess. This Histoire, however does fear Plutia's transformation and on a whim, Plutia has tormented her. Regardless, the two are close and probably stuck together ruling over Planeptune.
Plutia has met Neptune's Histoire, though the two have not really communicated specifically by themselves. That being said, Histoire also lectures Plutia by lecturing the entire group of goddesses. Histoire trusts Plutia to get the job done, but to get sidetracked while doing so, like all the goddesses.
Initially, the two are technically enemies, as Rei Ryghts wanted to stop goddesses from governing nation but after the two met and fought and foiled Rei Ryghts' plan. The two have gotten along with each other. Plutia is one of the first person to give this Rei Ryghts positive encouragement. By doing so, Rei Ryghts was able to assist the goddesses in the final fight and stop her power from overwhelming Plutia. Plutia acknowledges the efforts Rei Ryghts puts into helping and the two have warm relations.
Plutia wanted to talk Rei Ryghts out of the final fight, trying to make her see the joy of being a goddess and making friends. Afterwards, Rei Ryghts forgot all about her due to her not remembering anything after being given the other Rei Ryghts' power.
Plutia had trouble dealing with this little girl before Neptune got in the Ultra Dimension. Plutia is quite slow and Abnes can simply hurl insults at her. However, after Neptune gave her a talk down, Plutia does try to comfort the little girl much to her displeasure. Abnes does not trust the goddess but learns to throughout the game. In the end, Abnes accepts Plutia and Plutia holds no ill will towards her as well.
Arfoire fears Plutia and being around her transformation makes her shudder after her first kidnapping of IF. Arfoire decides to go around Plutia and target Neptune as a result of her fear. Plutia does not like her for kidnapping IF multiple times.
Plutia refers to Warechu as Mister Rat. Warechu first thought she was just a dumb girl but learned to fear her transformation. Despite his display of heroism to defend Arfoire, Plutia was not fazed and transformed and attacked him then tortured him excessively gaining a scolding from Compa for doing so. Warechu fears Plutia but Plutia likes the rat.
Like everyone else, Plutia finds Copypaste very loud. They may have started as enemies and eventually became allies. Copypaste started out hating all the goddesses but is now happy to be their ally. Plutia holds no ill will against this former enemy but would prefer him to not be so loud like everyone else.
Plutia has foiled Mister Badd's plans once and then tortured him. That being said, Mister Badd does not have a special kind of hatred towards Plutia or even an irrational fear of her. Plutia, however was willing to kill the transformed children defending Mister Badd and then Mister Badd but the other goddesses were able to stop her. Plutia was able to forgive Mister Badd since he tried to revert the children back and regrets his mistake.
Plutia and Anonydeath are both sadistic. Plutia has tried to kill Anonydeath but was foiled by various circumstances. She holds no ill will though and was happy to rescue him when he needed it. She does want to learn from Anonydeath the ways of teasing her best friend, Noire.
Plutia sees Bamo as an enemy to be defeated but does let her off easy by exiling her to a southern continent to start her own nation. Bamo also fears Plutia's transformation.
Regu has offered Plutia a chance to betray her friends and survive in the Sociomobilindustri, she wants to create. Plutia refuses and defeats this foe. Regu also fears Plutia's transformation. Plutia lets Regu like Bamo off easy by exiling her to a southern continent to start her own nation.