Mysterior is a mysterious new enemy of Linkara who appears in the Spider-Man: Power and Responsibility review.
Wearing a blue mask and a business suit, and refusing to reveal why he's Linkara's enemy, instead taunting Linkara with how it's better to solve the mystery of why he's his enemy than to explain why, to Linkara's mild annoyance.
Later, he switches to a yellow mask, took on the name, Mr. Enigma, and decided to, even more mysteriously, leave it ambiguous whether or not he's a hero or villain at all.
Mysterior is played by fellow Channel Awesome reviewer Phelous.