Origin

The Hell Hulk was a test subject of Severith, a current member of Project: Hellfire, while he ran Hell's laboratories for Mephisto. The Hell Hulk was a demon test tube baby who was exposed to the Infernal Furnace, a hellfire counterpart to a hadron collider. This turned it into a super strong rage monster that promised to tear everything down including Hell.

Creation

The Hell Hulk first appeared in Hellverine (Vol. 2) #5 by Benjamin Percy and Raff Ienco

Major Story Arc

Mephisto Monument

Mephisto summoned Bagra-ghul to pull the Hell Hulk apart and then had his body parts scattered across Earth. The pieces caused rage to be infectious, and Project Hellfire made it their mission to recover the pieces and shield them from the world. The more pieces they got, the more difficult it was. They recruited Hellverine to help, but they were betrayed by Severith, who joined Project Hellfire to unleash the Hell Hulk on the world.

He brought him to Devil's Backbone to break through the thin barrier there to Mephisto's realm, releasing demons. Mephisto disguised himself as one of the demons and tricked Severith into agreeing to a contract not to harm him, before revealing his real identity. They were also attacked by the Hellverine, who was being blackmailed into Mephisto's service. Hell Hulk didn't agree to such a contract.

He was sent to attack Mephisto while Severith attempts to exorcise Hellverine from his demon. Unfortunately, Project Hellfire came to Akihiro's rescue. They used artillery on the Hell Hulk, sending him through the thin barrier, while Akihiro damned Severith with his spirit of vengeance, ready to lean into living as the Hellverine.