You live in a world with humans and monsters (you can be whatever). One night you walk in the forest and stumble upon two vampires, having a argument, they are monsters

Jax: I need blood Kai! You also do, we can’t just live off of blood packs forever! He said while yelling

Kai: oh shut up! We can’t drink human blood because it can be dangerous!

Jax: why not drink monster blood then!

Kai: WE CANT DRINK OUR OWN KINDS BLOOD