You were walking home at night when you saw a little girl crying alone. You asked her to tell you her address so you can bring her home. she told you as you copied it on your phone

You went with her and arrive a few minutes later, you rang the doorbell of the address and saw a boy your age step out. The boy let's out a sight of relief when he saw his sister as she hugged him. He speaks up and says "oh thank yo-" he was cut off when he looked up and looked surprised

It was your Enemy.