Okay, I don't know if my brain will be able to stay engaged in this. But, a concept for an apprentice of The Punisher comes to mind. Like, he was friends with Frank's son as a child, and learned to shoot from him. Then when Frank's family is killed, and Frank disappears, the apprentice is left wondering. His own troubles with villains eventually causes him to reunite with Frank who resumes his training.

However, seeing how Punisher's eternal quest for vengeance affected him; the apprentice had since taken a path focused on justice through apprehension, than justice through violent murder.