Gakuen Soshiki

An orphan whose family was destroyed by the underworld discovers a shocking truth—the very organization that took everything from him was built by his own father. Fueled by vengeance, he infiltrates a school that trains future crime syndicate leaders, determined to take down the traitor responsible for his mother's death. Surrounded by enemies, he must climb to the top through sheer strength and strategy. The battle for revenge begins now.

(Source: Shueisha, translated)