Ben 10: The outer stories is a series of side-stories taking place around the same time as Alien Force and Ultimate Alien. This focuses on multiple mercanaries, each with their own intentions.
Said mercenaries are:
Crash, a Kinceleran with a desire for profit.
None of these individuals get involved in the center story, but they do wind up on Earth, where a race for power gets them to fight amongst themselves. Each character's past and personalities are explored through the episodes, allowing for a combination of action sequences and character developement.