He is a pinkish alien with blue eyes who wears a golden armor with a halo on top of his head.
When he was bad he was a pale-ish blue pyrotic humanoid with red and green eyes and weared a all-black armor. He was a prince of a planet who turned to the dark side when his father, the king, took his sock from him as a toddler which at the time was his only friend. This became Destructor a truly evil and tyrannical ruler who made his people miserable, tortured/executed anyone over any reason and he even locked away his own father.
When Wander and Sylvia found his old sock years later and find inside owner's adress they went to Destructor's scary Kingdom and evaded his guards. Finally, they found Destructor but, before Wander could ask if the socks is his, he ordered were executed.
Wander and Sylvia ended tied to a chain-linked rope dangling over a huge cauldron of boiling oil and, while the executioner lowered the crank; Wander, aching for failure, tried to get rid of the sock and dropped the it into the cauldron, but Sylvia, convinced that it actually mattered to her friend, caught it with her tail before it went into the liquid and threw it to Destructor asking if it belonged to him. Destructor recogniced his old friend and was redeemed and told the guard to release them and all the prisoners and make them dukes, except for one prisoner, whom he told to make an archduke.
When he was captured by Lord Hater in episode "The Rager" it were shown he may still suffer from a few close calls, but his sock helped to keep his behavior under control.