AF Kevin and Ben
Kevin Ethan Levin is an Osmosian and a member of Ben's Team. When Kevin first appeared in the original series, he quickly became one of Ben's most notable enemies. However, he reformed in Alien Force, and became one of the main characters until his departure, along with Gwen in The More Things Change: Part 1.

Ben 10: Alien Force

What Are Little Girls Made Of?

Ben 10 Ultimate Alien

Absolute Power, Part 2