Yu Narukami (The Sister Complex Kingpin of Steel) is the main protagonist in Persona 4, the 4th main installment in the Persona series. He's one of the playable characters and main characters in it's fighting game sequels Persona 4 Arena and Persona 4 Arena Ultimax.
He returns in BlazBlue Cross Tag Battle as a playable character and as one of the four main protagonists.
The leader of the Investigation Team, a group of Persona users from Yasogami High investigating the mysterious kidnappings and murders around their town. In 2011, he transferred to Inaba to live with his uncle and cousin while his parents worked abroad. Through his friends, he learned about the Midnight Channel, a rumor stating that those who stare into a blank TV at midnight while it is raining will see the face of their soulmate. He soon awakened to a special power, allowing him to enter a dimension inside the TV and fight creatures called Shadows using his Persona, a manifestation of his inner self. When Midnight Channel-related murders struck Inaba, he formed the Investigation Team to prevent more from occurring, and to eventually track down the killer.
After solving the murder mysteries, including how he and the culprit Tohru Adachi got their Persona powers, Yu returns to his old school where he was transferred from. Few months later during his visit back to Inaba for a reunion, Yu and his friends all end up being the subjects to a Midnight Channel fighting tournament known as P-1 Grand Prix hosted by "General Teddie", and are dragged into this bloodbath tournament for the culprit's deadly entertainments. Once entering the tournament, Yu and his friends find their missing allies, while meeting members of the Shadow Operatives.
- In the English version of Persona 4 The Animation and the Persona 4 Arena games, Yu and the Investigation Team refer to each other on a first name bases with an honorific except for Teddie (Kuma in Japan). In BlazBlue Cross Tag Battle, Yu and the Investigation Team refer to each other on a last name basis. For Yu's case, this was likely done to avoid confusion as his name Yu sounds like the word "You". However, Yu and probably the rest of the Investigation Team still use honorifics as evidenced by Yu calling Ragna the Bloodedge "Ragna-san" in their special victory screen dialogue.
- Due to Investigation Team have already met Shadow Operatives, and Yu already returned in his old high school at Tokyo, as mentioned in Persona episode, this leads BlazBlue: Cross Tag Battle alternatively takes place after Persona 4 Arena Ultimax.
- His along with Aegis’ Arena remix theme still not have ”in Mayonaka Arena” (which is mainly for Eastern/Japanese version) replaced with simply as “Arena ver.” on their BGM name in Western version
- Yu's title, The Sister Complex Kingpin of Steel, refers to his great familial love and care as well as his protective nature towards his cousin, Nanako Dojima, who is like a little sister to him.
- Yu has color palettes of the following characters: Ryoji Mochizuki (Persona 3), Ragna the Bloodedge, Blue Haired Boy/Makoto Yūki (Persona 3 Protagonist), Hyde Kido, Ruby Rose, and Joker/Ren Amamiya (Persona 5 Protagonist).