When his brother Jonathan volunteered to be used as a test subject to become the ultimate soldier, Quick Stryke tried to talk him out of it. The experiment ended in disaster and his brother went crazy and attacked Quick Stryke. In the struggle a weapon was fired and hit some gas tanks which resulted in a massive explosion. When the smoke cleared Jonathan was dead.
Quick Stryke blames Iron Klaw for Jonathan's death and thus hates Iron Klaw, for experimenting on his brother and causing him to go crazy and die. Since that day he has dedicated himself to bringing down Iron Klaw and SKAR. Quick stryke had been fighting a solo / private war against Iron Klaw and SKAR before joining the GI Joe team.
Lt. Stone and Sgt. Savage respect Quick Stryke's ability but it took them a while to actually trust him fully. After Quick Stryke led a successful mission that had him face Iron Klaw and choose between SKAR and GI Joe (which Lt. Stone observed), he has become fully trusted by the GI Joe team.
His need to avenge Jonathan's Death and to prevent more people dying like his brother, is his source of inspiration and motivation. When Iron Claw was thought to have been killed after the Joe team learned of his secret identity as Count Von Rani, Quick Stryke thought his reason and purpose in life was finally realized. Unfortunely for the world Iron Klaw survived and Quick Stryke's need to avenge his brother with the fall of SKAR and Iron Klaw has been renewed.
A Quick Stryke figure was planned, but never released.