Killspree's history is unknown and remains a mystery even after joining Department K, and it's a covert group known as Weapon P.R.I.M.E. His joining the team after Grizzly left as his replacement or by happenstance is unknown.
Killspree under the code-name Killjoy first saw action when Domino and Grizzly, posing as Val Cooper and head of Department K's General Clarke broke into the department's bunker to steal classified files.
Being sent to stop the infiltrators, Killjoy slipped away unseen while Grizzly explained who his ex-teammates were, though he did not know who Killjoy was as Weapon P.R.I.M.E. kept the two busy. Killjoy coming out of the shadows behind Domino introduced himself as he nearly decapitated her. But she managed to dodge the sneak attack thanks to Hammer who was keeping an eye on them while secretly downloading the files they came for. After Killjoy hurt Grizzly he took a face full of magnesium flare from Domino, which Grizzly blasted a way out through a sewer above them. Killjoy and the others were unable to catch up to the two as they escaped in Hammer's RV which turned into a jet.
Despite Alpha Flight being suspended for the foreseeable future Northstar would not stand down and continued his activities[3]. Wanting Weapon P.R.I.M.E. to replace Alpha Flight as Canada’s preeminent superhero team, General Clarke sent Killjoy now called Killspree, and the team to capture and remove Northstar from the public eye under Military Ordinance B-6345.
Killspree and the others headed to Northstar's villa on the coast of Ibiza, Spain; where they spotted a car believing it was Northstar's Killspree hung back as Yeti and Double Trouble dealt with the car. With the car off the road, Killspree ripped the roof off it when Tigerstryke had him stand down, but unfortunately, they found that they had attacked the wrong guy. After ransacking Northstar villa and learning that he gave them the slip, Killspree angrily slashed his computer to bits. Thankfully due to Tigerstryke's suit's tracking tech they were off.
Finding Northstar in Paris (France) choosing not to come peacefully, they were forced to fight back. Killspree nearly matching Northstar's superhuman speed was able to land a blow before being thrown into the twin's connecting plasma chargers, causing an explosion.
With Northstar having escaped Tigerstryke and Yeti they tracked him down to Zuyevo, Russia; but this time Northstar was gonna give up and let them arrest him. But Killspree wasn't buying and was warning Tigerstryke when out of nowhere he was hit by a thrown crowbar from the circus's strongman. Caught off guard Killspree was stunned when the rest of the circus performers attacked, but he was able to recover quickly to help. Hearing Northstar telling Tigerstryke that the civilians are under mind-control by Arcade Killspree and the others hold off the people as Tigerstryke and Northstar destroyed Arcade's mind-control device. With the people free and Killspree warning everyone the local law was coming, they thought they were no longer not wanted but were under orders and went to arrest Northstar. Just then the power went out and Killspree couldn't see a thing, not even the mystery attacker (Guardian) who blast Tigerstryke stopping him from stopping Northstar's escape.
Despite tracking Northstar to New Orleans Tigerstryke called off the hunt.
