Ruri Gokou (五更 瑠璃, Gokou Ruri), also known in the otaku community as Kuroneko (黒猫) is part of the supporting cast of Oreimo. She is an avid fan of the fantasy seinen series Maschera, and hates anime that focus on moe and cuteness to sell (e.g. Kirino's favorite anime Stardust Witch Meruru).
She is voiced by Kana Hanazawa.
Her choice of fashion is predominantly gothic lolita, and is always dressed in a white frilly top with a black bolero worn over it. She also wears a black skirt with cross-shaped detail and black Mary Janes with gray stockings. On her head is a headband with a small red rose adorning each side.
Kuroneko is 160 cm tall and weighs 43 kg. Her measurements are B77 / W53 / H80.
Ruri often acts according to the character she poses as (i.e., the Queen of Nightmares, an antagonist in Maschera): snobbish and overly confident of her own aptitude. However, she is in fact socially insecure, and is uncomfortable in talking to other people. Fortunately, she eventually learns to make friends when she enrolls in high school once again.
Aside from her otaku persona, she is also a caring sister to her younger siblings Hinata and Tamaki, whom she constantly tends to while at home.
Ruri came from a financially-challenged family, and with her parents often away, she is left to take care of her younger sisters Hinata and Tamaki, temporarily leaving behind her studies. Her costume, as proof of her skills in sewing, is completely done by hand, and she also occasionally uses her expertise in sewing to fix her sister's stuffed toys.
At one time, Ruri joins the online community Otaku Girls Unite! as Kuroneko, and eventually attends one of its offline meetings, although not expecting to make friends at the said event.
Even though she started off as haughty even toward Kyousuke and despite the fact that Kyousuke at first seems to dislike her, eventually, they seem to get along. They share the same rationality, and seems equally apalled over some of Kirino's childish acts and likes.
Later in the manga, they appear to be calling each other on the phone without a particular reason. Kyousuke invites her and her alone to go out on a Maschera convention despite him not being interested in the anime.
Even later in the manga, she parodies and denounces in one of her mangas the fetishism Kirino seems to have toward her brother, showing her literally smelling his underpants with an ecstatic expression. Kyousuke noted that she made a mistake because Kirino never called him "Onii-chan"; she reacts by acting shocked and saying she felt sorry for him. She then starts to call him Nii-san and makes showy advances to Kyousuke, parodying the kind of eroge Kirino plays, literally making sexual advances toward him, making Kirino jealous.
Near the end, while she gives a call to Kirino, she keeps referring to Kyousuke as Nii-san. Kirino reproaches it to her, complaining that Kyousuke goes "all dere" (meaning to become "lovey dovey") when she calls him like that. Kuroneko then replies by saying, she'll soon enough call him another way. This is shown when Kuroneko attends Kyousuke's school at the start of her highschool years, and sure enough, she refers to him as Sempai (a respectful way of addressing a senior).
She becomes his lover at the end of Volume 7.