Short Fuse
Speak with A-Bomb in Hala to begin this roaring rampage of semi-revenge.
Follow him through Hala, Manhattan Noir, and Egypt, fighting the enemy groups you encounter.
This is sidequest has a lot of fights and a lot of specialist fighters- don't be afraid to swap out characters to get the skill set you need for the next wave.
Running the gauntlet unlocks A-Bomb for purchase (he has the Stealth skill, unexpectedly enough), and also unlocks a new Wonder Man mission in Manhattan.