I've heard we have an enemy is common

Damien: He left me for dead. He never once tried to help me, even when I was human. He never even looked for me! And now he treats me like shit. So, you could say we don't get along.

Sera: You're not the only one he's left and forgotten about. Kiluri's hurt me, too.

Damien: So, it looks like we have something in common.

Sera: The enemy of my enemy is my friend.