Mentor

Mentor is the brother of Thanos.

Biography
Mentor joined Drax, Nebula, Pip, and Silver Surfer in a quest for the Universal Library. However, they found it was overrun by Virals, the Watchers who sought too much knowledge and turned into the creatures for their greed. Drax, Pip, and Silver Surfer got away but Mentor was turned into a Viral.

Background
Mentor was voiced by Cedric Smith, who played Professor X on.

Currently the only version of the character outside the comics.

In the Comics
Is the brother to Starfox, who has yet to appear outside the comics, and has no relation to Thanos.