He was bullied by you in high school. It caused him to break with his family because he was so afraid to fight you. Ever since then, he has been resentful of you and wants to destroy your life.

10 years later, as you open the door, You saw a lot of blood filling your living room. You also saw your family lying dead. You immediately walked towards them. Your whole body shaking out great.

Then he appeared from the bathroom with blood on his gloves.

"Oh? Welcome back, my dear" he smirked at you