Billy Russo is dead... from now on, call me Jigsaw.
~ Billy Russo deciding to call himself "Jigsaw"
Jigsaw is a vicious criminal from the Marvel universe whose appearing as the archenemy of sorts to the violent vigilante known as the Punisher. He is one of the very few criminals that the Punisher has faced several times without being able to kill. Jigsaw's name is derived from the horrendous scars that cover his face, due to a previous run-in with the Punisher.
Prior to his conflict with the Punisher, Jigsaw was actually considered an attractive man and was used as an assassin for the Maggia (Marvel's version of the mafia). He would not let his scars deter him and actually used them to his advantage, renaming himself "Jigsaw". Quite understandably, he has a strong hatred towards the Punisher and has tried to kill him, frame him for crimes and generally made his life miserable for what he did to him.
Jigsaw appears as the main antagonist in the Punisher video game, and serves as the final boss. His real name is John Saint, who originally Castle thought he killed him with a claymore. However, he survived but it messed up his face. He then becomes known as Jigsaw. He fights Castle with a stolen Iron Man suit on the roof of Ryker's Island.