Hunter X Hunter: Seven Deadly Sins

After transmigrating into the Zoldyck Family, he became Illumi's twin brother and the elder brother Killua feared and respected.

He began assassination training at the age of three and started carrying out missions at six.

With blood on both hands and a mountain of corpses beneath his feet, his legend began with his life as a killer.

Hunter x Hunter, Demon Slayer, One Piece.