Killing Killer

The protagonist, Siwoo Lee, experienced the loss of his parents at the hands of a murderer a decade ago. At last, he confronts Jack, the killer responsible for his parents' deaths, and decapitates him. "It wasn’t me who killed your parents." Upon discovering that the actual perpetrator is a "contractor" associated with a collective of assassins wielding superpowers, Siwoo Lee resolves to track down the members with Jack's assistance.