Mortar and pestle are like Bonnie and Clyde, and they realized they kept getting stopped by super heroes when they do big jobs, so they are sticking to small time robberies in small towns and making bank over time.They get thwarted in the first couple of scenes, then they get super powers, and put up a much better fight.

Mortar starts as a grenade launcher wielding human, and turns into a fireball throwing Extra. He is very bombastic. Like Mick Rory from Flash/Legends of Tomorrow, or jack Nicholson's joker.