Out of all the CPUs, Noire is the closest to Neptune. They are quite the opposites in personality, Neptune is lazy while Noire is a workaholic, Neptune can be read as an open book, Noire is nowhere so honest. Despite the difference in work ethic, Noire is willing to admit, no matter what, Neptune is her equal. She finds herself, usually at the end of Neptune's jokes one way or another even if she attempts to make fun of Neptune. In Hyperdimension Neptunia Victory and its remake, however, due to Noire winning the real life popularity contest, Neptune does not have such a high opinion of her and is partially driven by a desire to return to the Hyper Dimension to get revenge over the loss of her popularity but regardless, the two are always close. In Megadimension Neptunia VII, the two are once again closer as Noire is willing to fly at mach speeds to Planeptune just to assist Neptune. Neptune also has a knack for learning secrets about Noire and will tease her about it. Due to both goddesses being part of the main cast, they have gone through a lot and became very good friends.
She sees her flaws in this Noire and finds that rather embarrassing. The two do not get along as well as the other goddesses and their Ultra Dimension counterparts. That being said, the Ultra Dimension Noire felt bad for her since, the Hyper Dimension goddesses were able to look cool defeating the fake goddesses while she abandoned her Hyper Dimension counterpart keep the barrier open in the true ending of Hyperdimension Neptunia Victory and its remake.
Vert acts as a maternal figure to all the CPUs and Noire is no different. In Hyperdimension Neptunia mk2, she scolds Noire for trying to hide her greens in one event. Vert does also know how to push Noire around, when she appealed to her cosplay hobby to get Noire to agree to being produced as an idol. Due to both goddesses being part of the main cast, they have gone through a lot and became very good friends.
Noire has seen the other Vert but the two have no significant interaction. She is unhappy that this Vert along with the other goddesses abandons her to keeping the barrier open.
Blanc and Noire are not really seen interacting much except with all the other CPUs around. However, they are comfortable enough to hang around Planeptune and play games into the night with the other CPUs. The two are the more harder working of the goddesses. Due to both goddesses being part of the main cast, they have gone through a lot and became very good friends.
Noire has seen the other Blanc but the two have no significant interaction. She is unhappy that this Blanc along with the other goddesses abandons her to keeping the barrier open.
Plutia was excited to see another Noire, but the two have no significant interaction meaning Noire does not fear Plutia or her transformation which she is unaware of.
Uzume has played a crucial role in helping Noire and the other CPUs break out of their whirlpool of delusion. Uzume is of an older generation of CPUs so she does consider herself a senior to Noire and will do whatever it takes to help her juniors. Noire, in turn joins the cast in helping Uzume cope with her new memories. The two have worked together in the Heart Dimension to save Gamindustri.
Noire trusts her little sister Uni to back her up and is proud of her. However, she will admit in Hyperdimension Neptunia mk2, that Nepgear is stronger than her. That all changes in Hyperdimension Neptunia Victory due to Nepgear and Neptune being lazy for three years. As Noire is a perfectionist, she does try to be the perfect older sister to Uni, which only drives the two to doing a lot of work to out do each other to impress one another. Uni has no idea Noire had any flaws until see the two Noires interact but that does affect Uni's overall opinion on her sister. When Vert was producing Noire and Uni as an idol, Noire put a lot of effort into the costumes which Uni was happy about.
Noire spars with Nepgear on occasions in Hyperdimension Neptunia mk2 since Nepgear finds her more reliable as a training partner than her older sister. Noire views Nepgear as the older, more responsible sister who has to take care of Neptune. The two get along nicely.
Noire has no significant interaction with Rom but the two probably get along well enough.
Noire has no significant interaction with Ram but the two probably get along well enough.
Noire gets along well with K-Sha, as the two worked together after the rewrite of Gamindustri. While Noire was initially upset that K-Sha wanted to kill Uni to spend more time with her, K-Sha helps save Uni after the Order leader poisoned her. The only issue that Noire has with K-Sha is their "relationship". K-Sha has a one sided love for Noire. Noire treats her happily as an irreplaceable friend and has scolded her when she thought otherwise. When Affimojas publishes an article based on what K-Sha told him, Noire states that no matter how it is read, it sounds as if the two are lovers.
God Eater was sent from the Lastation Defense Force to help Noire out. Noire ends up helping her first by giving her some food. The two have a rocky start together as God Eater shoots Noire by accident as the two were trying to defeat a monster. Noire forgives her and the two worked together in dealing with the Gamindustri Rewrite and Heart Dimension. The two have run into trouble with God Eater's God Arc and his habit of eating clothing but the two get along well enough.
Noire's trusted oracle is Jinguji Kei, the two have an efficient working relationship. Despite the fact that Noire was missing for 3 years in the Gamindustri Graveyard, Kei decides to leave things that Noire has authority over to pile up. When Noire returns, she complains about the work that Kei did not help her complete, but somehow completes all the work anyways. Uni says that is how they usually work and it works out really well. Kei has shown concern for Noire's disappearance in the Graveyard meaning the two care for each other beyond the working relationship. Kei can read when Noire is focused on her hobbies over her work even when Uni thinks all Noire does is work. The two get along well as expected of a Goddess with her oracle.
Histoire trusts Noire, and all the other CPUs enough to help maintain Planeptune while the two CPUs are away in the Ultra Dimension during Hyperdimension Neptunia Victory.
Noire probably sees Linda as an underling and constantly defeats her with the party. Noire did however, want to capture her, at a point, to make her cast her vote for Noire, for most popular goddess. The two do not get along.
Noire sees this rat as an enemy and constantly defeats him with the party.
Noire has a grudge for losing to Magic the first time was able to settle it by destroying her in the end.
Noire knows of Brave's chivalry and does try to help Uni defeat the resurrected Brave since that Brave lacks that honor the original Brave had. Additionally Noire was shocked by Brave's marriage proposal to her sister from beyond the grave. She refused and was relieved to find it a dream.
The two do not have any significant interaction except for Noire along with the party destroying him.
Judge guarded over the Noire and the other goddesses in Gamindustri Graveyard. Other than that, Noire along with the party destroyed him.
Noire sees this enemy as a legitimate threat to all of Gamindustri. She was willing to fulfill her duties to defeat even at the cost of her life. Luckily, that was not required.
Noire, Blanc and Vert were sent to defeat Rei and reclaim Planeptune. However, the three were either defeated or forced to stop to allow Neptune and the others to reach Rei without hassle. The damage caused by Rei did increase Noire's workload causing her minor inconvenience. Rei forgot all about Noire due to forgetting everything during having her counterpart's power.
Noire and the other Hyper Dimension goddesses chased this Rei around delaying her from reaching Neptune and the others in their fight with her counterpart. Noire had assumed it her dimension's Rei.
Noire has shut down the original Order but this woman managed to escape and take over Lastation in the Gamindustri Rewrite. The woman is planning to make Lastation go to war and has ordered assassinations on Noire. Noire dislikes her and would stop at nothing to prevent her nation from going to war. The Order Woman has been plotting to counter Noire and the CPUs. In the end Noire was able to defeat the woman and bring her to justice.
Noire saw Affimojas as a threat to Gamindustri and worked with the other goddesses to stop him. Affimojas was defeated and later put on probation for helping the CPUs. The two don't seem to get along, as when she goes to confront him about the article he published, threatens to throw him in jail despite being in probation.
Noire and Steamax were enemies and after Noire defeats him with the cast, she does note his tenacity is impressive. Despite ending AffimaX, Noire does not heavily punish Steamax for his actions.
Kurome has captured Noire and made her fall into a whirlpool of delusion. However, Noire got out and opposes her plans. Noire does come out victorious with the cast as they defeat her and save Gamindustri. Noire and Kurome dislike each other heavily.
Noire is willing to put her trust into this other Neptune simply because she is a "Neptune". She believes this Neptune has all the traits of "Neptune" being heroic, childish and trustworthy. The other Neptune does not think much of Noire but the two did work together in the Heart Dimension to save Gamindustri.