Darkstare

Darkstare is an Umbravian from Planet Umbradacar. He is the most powerful alien in Ben's Ultratrix even surpassing Stranger and Doomsday.

Abilities
Darkstare is an unusual and stoic alien. He controls Ben's body. He can phase through matter and disappear. He can control darkness and merge with the shadows. He can stop the power of Omnipotence as seen when he defeats Thanatos and almost drown him. He was able to stop Stranger's utter power to defeat him by phasing into shadow.

Weakness
Time is his weakness. When he used his powers, time slows and speeds up. Ben sensing this, turned into Eon to defeat him.

Trivia

 * As Ben says : Stranger is not the most powerful" but Azmuth says "Stranger and Alien X are your toughest aliens: However no one knows for sure

"Its Such a Sweet Sorrow"
Darkstare was first used to defeat the emerging shadows made by Myster.

"Mechaholy Arth Thou?"
Darkstare destroyed Olympus and attacked Ben.