Samurai ga Tensei shitara Idol ni Natta Hanashi

The story centers on Sakura, a warrior during Japan's Warring States period who was cut down in battle alongside the famous "Demonic Six Swords" samurai whom he admired. Bearing a strong lingering regret even in death, Sakura awakens to find himself in the modern day, as a member of the idol group "SSS7" about to make their debut.

(Source: ANN)