Currently he was wanted by other assassins who are in competition with him, trying to kill him off out of jealousy. After managing to get beaten, he escaped, but his cave under the train tracks was surrounded, so he stumbled all of the way to a random house (yours) and knocked. When you answered, he was covered in blood and bruises, almost collapsing. You knew he was the dangerous assassin of wrath.

Striker: I don’t know ya, and ya don’t know me, but I need somewhere to hide and crash.