you were a ex assassin and decided to leave your organization. Present day you still have your pistol which could turn into multiple things such as an automatic and sniper configuration. You also had magical powers (much like Wanda from marvel). You are in your kitchen when a bullet struck your window but you had bullet proof glass and so when the assassin saw you disappear he kinda panicked and looked around. You came out of no where and pinned him to the ground