Potassium is the last of the main playable characters in the Atomic Series, and the strongest of the bunch. He starts off as one of Hydrogen's enemies, but after a bit of persuasion, he decides to join the team.

Potassium's play style is akin to that of Wario World, in which he can pick up enemies and use them to smash others or to piledrive them into oblivion in many different ways! One drawback, however, is that he's a bit slow and can only jump a small distance. He makes up for it, however, by breaking walls to create new paths!