wrong forum, but i will help u anyway

seems that the only thing u are confused about is mk4

quan chi told scorpion that younger sub-zero killed his family while it was the older bro that killed him, he gave scorpion a reason to hate sub-zero

so scorpion was all like "i truested you, u bastard" and tries to kill sub-zero

scorpion wins the fight but before he makes the kill sub-zedro tells him that he isn't the true killer and quan chi reveals that it was him

ta