Psyphon

Psyphon (possibly a play on "siphon", meaning to drain or leach, due to his aid in draining the heroes of the conquered worlds) is an alien with a large horn coming out of his head who serves as Vilgax's servant and right hand man. He has a very close resemblence to a To'kustar. He is extremely loyal to Vilgax and follows his will completely. He has a skeletal appearance and helps Vilgax to drain all the powers of the heroes of the 10 worlds he had conquered (Dwayne Mcduffie confirmed one of these worlds was his home world). Still nothing much is known about Psyphon except for the fact that he appears devoted to Vilgax and he also shows sign of arrogance towards the people of Earth. He appears in Vengeance of Vilgax helping Vilgax

Psyphon also appeared briefly at the beginning of Primus, and made a non-speaking cameo at the end of The Secret of Chromastone, handing a tissue to Vilgax, having caught Ben's cold.

Psyphon appeared in The Final Battle: Part 2|The Final Battle assisting Vilgax on betraying Albedo and conquering earth, And was defeated by Ship and send to the Plumbers' jail.

He made an appearance in the game Ben 10: Alien Force Vilgax Attacks as a mini boss and is met by Ben on the rooftops in Bellwood. He then brings the Mr. Smoothy sign to life with alien technology. At the end of the game, he was sent into the Null Void with his master by Ben as Alien X.

Powers and Abilities
Psyphon possesses no actual powers, but has advanced technology far beyond Earth standards.

During the episode Vengeance of Vilgax: Part 1 when the police shoot him, he stops the attack by pressing a button on his wrist and a force field appears. He then throws a grenade at the police and it exploded, destroying everything within its large blast radius.

In the Vilgax Attacks game, his abilities range from orbital lasers to force fields to energy attacks and grenades. He was also able to bring a Mr. Smoothie drawing to life (like Charmcaster did in the episode In Charm's Way) with a laser and make it into the big boss in the level.