I’ve always felt that the biggest mistake most OCs (original characters) in Tokyo Revengers fanfics make is trying to become invincible fighters who steal the spotlight from the Toman captains (basically turning into a "second Senju").
With that in mind, I came up with a concept for Takemichi’s cousin following a strict rule: she doesn't fight in gangs and has very little screen time, yet she acts as an emotional anchor behind the scenes—much like how Shinichiro functions in the canon story.
I wanted to share her structure here to see what you guys think about how she fits into the plot:
Who Takemichi's cousin is & his missing link
• Appearance and background: She is an orphan who lives with the Hanagaki family. Because she has foreign-looking features (pearly vanilla-blonde hair and a "porcelain doll" appearance), she suffered heavy bullying and xenophobia at school back then. Out of sheer survival instinct, she learned how to defend herself ("she hits to knock out"), though her actual personality is witty, sarcastic, and very practical.
• From "hero" to "delinquent" (fixing a canon gap): As a kid, Takemichi dreamed of becoming a hero. The anime and manga never really explain why he suddenly dropped that dream and started thinking delinquents were cool, even though heroes and delinquents are complete opposites. In my version, his cousin is the answer: he bleached his hair blonde and embraced the delinquent label to show her that she wasn't alone and that the prejudice she faced wasn't her fault. He never stopped wanting to be a hero—he just changed how he protected her.
•The repressed trauma: In their final year of middle school in the original timeline, when Kiyomasa goes after Hina (who is her friend), Takemichi’s cousin steps in to defend her and ends up being killed by Kiyomasa with a baseball bat. Takemichi develops such severe PTSD that his brain blocks out all memories of her—which explains why he ran away from town and became such a broken adult who apologizes for everything.
2. Entering the story without forcing the spotlight
• The memory trigger (Moebius Arc): On his first time leap, Takemichi doesn't even remember her. When he returns to the future, Naoto tells him that he can also save his cousin (without giving him time to ask questions, rushing straight into studying the past). When Takemichi runs into her in the past, the mental block shatters and he breaks down crying in front of her—while she just drops a dry joke ("You somehow managed to get even weirder than usual") and hands him a candy to make him stop crying. From that point on, stopping Kiyomasa also becomes a race against the clock to save her.
• Brief, comedic appearances: She doesn't attend Toman meetings. During the scene where Mikey and Draken fight at Takemichi's house (after Pah-chin gets arrested), she simply comes home from school, sees the trash on his head, asks "Takemichi, why is there a poop on your head?" and walks inside without caring at all about Toman's leaders. She only casually reappears at the festival after the Black Dragons arc, having naturally befriended Emma and Mikey outside of gang life.
3. The big twist: Kisaki’s obsession ("Greenhouse Flower" vs. "Asphalt Flower")
In canon, Kisaki’s motivation feels a bit shallow since it’s just unrequited love for Hina. Here, his real target was Takemichi’s cousin:
• When they were kids and Takemichi saved Hina from bullies, his cousin was there and told him that while he needed to learn how to defend himself before protecting others, he wouldn't be a good man if he hadn't stepped up.
• Kisaki overheard this and started watching her. In his twisted mind, Hina was a "greenhouse flower" (it’s easy to be kind when everyone loves and protects you), whereas Takemichi’s cousin was an "asphalt flower" (she grew through hard concrete, surviving orphanhood and prejudice without losing who she was).
• Because his cousin ends up dying in one of the past timelines—and Naoto, focused solely on his sister, doesn't pass that info along to Takemichi—Kisaki kills Hina in every future because he believes Hina is the "wrong survivor" and blames her for his cousin's death.
4. The Bonten Arc and the "Ivory Tower"
When Hina finds out about the time leaps and warns Mikey and Draken during the Tenjiku arc, Mikey keeps someone watching over Takemichi’s cousin and ends up saving her from a fatal mugging.
• In the Bonten timeline, after losing all his pillars, a corrupted Mikey decides the outside world will take her away from him too. So he locks her away in a luxury penthouse in Tokyo (Aman Residences).
• When former Toman members try to rescue her, she refuses to leave: "If I walk away, the city burns. I chose to stay—don't come looking for me again." She becomes a voluntary hostage to contain the monster Mikey turned into.
• This gives way more weight to Takemichi risking his own wedding to go after Mikey: he isn't just doing it for a friend, he's doing it to free his own blood cousin who sacrificed her freedom for all of them. And on the rooftop, Mikey gives Takemichi the penthouse address right before jumping, trying to set her free through his own death.
5. The Final Timeline
With the past rewritten and the new Toman (Mikey as leader, Takemichi as co-leader, Draken as vice-leader) acting as a natural shield, Takemichi’s cousin grows up free from bullying, Kisaki never develops his savior obsession (since she never needed saving), and her witty, sarcastic humor thrives freely alongside her friends and family.
What do you guys think of this approach to an OC? Do you feel it works well to add more weight to Takemichi’s and Kisaki’s motivations?