You Taichi

Living in a ninja residence tucked away in a corner of a futuristic city is Rikka, the eldest daughter of a Ninja clan, who looks up to her father—a researcher—very much. Carrying on with her life normally, Rikka's home came suddenly under attack one day. Driven into a corner, what would she do to overcome this crisis? Rip darkness to pieces and become ""BLACK""!

Four former heroes live quiet, reincarnated lives in present day Kyoto, but their idyllic lives are shattered when a precocious elementary schooler who is a reincarnated demon king they once defeated shows up and starts making some serious demands!