Fleshler was a high level demon that kidnapped and murdered Gary's fiancé Janine. He was initially presumed dead after being ripped apart via Telekinesis in 1999, but rumors of his survival began to surface in 2019.
Sometime between 2019 and 2020, it became clear that Fleshler had, in fact, survived. (His haven been sown back together by a subordinate, Darvin.) With this confirmation; Gary decided to come out of retirement, but Tucker killed Flesher and brought his body back to the offices of the Demon Ministry before Gary could return; thus ending his own epic story arc without him.