Jase is the main protagonist of the entire "Killing Spree" Series.
Jase wears his blue baseball cap backwards, and is written K-S (it stands for Killing Spree). In Killing Spree 7, Jase loses his hat and the bullet wound from Barry's gun can be seen covering almost his entire face. Up from Killing Spree to the First few scenes of Killing Spree 4, his eye pupils were black. In Killing Spree 4 to 7, his eye pupils were red. He is just a stick figure, so he has no other physical characteristics.
Jase lives by himself. He does have a family, but according to Master-Samus, he was given up for adoption. When he was about 17 years old, he went to a gypsy (Glenda) that gave Jase 1 day to do whatever he wants to do for $10, and Jase decided that he would kill many people. His first victim was his principal, and his next victim was the gun shop owner nearby.
Jase's best friend, Jimmy, came along with Jase to kill people with him (although he never killed any victims), but however, in Killing Spree 6, Barry, a police officer killed him. Jase began to feel rage after that, however, he was also killed.
In Killing Spree 7 Jase comes back to life by getting the crystal balls powers. Then Jase goes to find Barry and battle once again and Barry wins and shoots him 3 times in the head. After a flashback that showed how he and Jimmy met, Jase is revealed to be immortal, then gets a chainsaw, puts The Killer's mask on and kills Barry with a chainsaw.