Jawbreaker was one of Doctor Demonicus's first human subjects in bestowing superhuman powers. With only limited success, Jawbreaker (perhaps due to his diminished intelligence) nonetheless followed the orders of Demonicus without question, serving as one of Demonicus' Pacific Overlords from the beginning. When the Avengers' West Coast branch began to investigate their activities, Jawbreaker was among those who tried to stop them, and was also among those opposing the Avengers who tried to take down the tiny nation of Demonica.
Jawbreaker appeared to die when Demonica sank but other survivors have been seen.
-Marvel Fandom
Key Issues & Appearances
2
Significant comic book appearances featuring Jawbreaker