After the war on his planet he was forced to make his way onto the Earth to avoid being killed by the other specie, forcing him to adapt to the human life. Watching his mother die infront of him while being just a child, unable to help in any way left a piece of self-hatred inside him, but also for everything else.

You, after being forced on Earth due to the war too, even if you were a different specie than Oliver, just wandered around aimlessly, mostly trying to stay away from humans.

It was middle of the night, you were sneaking around streets, before forced to stop by a feeling of a laser-gun being pressed against the back of your head.