Mark

Mark is a supporting character, in the episode; Hammer and Fail Parts 1&2 plus makes a cameo in Space Face: Part Two. He is seemingly a negative twin of the character; Matt

Physical Appearance
 He carries a resemblence to Matt, the difference being, Mark has blond hair and a turtleneck  instead of a hoodie. Mark also has a cleft chin.

Traits
Mark has a British accent of the southern (London) area, as does his friend Jon