Oki doki! Next was. . . .

"Two blood drinkers works just fine for me. So long as you mean creatures that must drink blood to survive, and drink little to nothing else. I'm trusting that a blood-craving won't be limited to only two?"

Yes, two that drink blood to survive, one on each side. And yes, there are other races that enjoy consuming blood, however they must feed on more than that to survive.