Marcus
So why couldn't Viktor kill Marcus? Did he need his pure blood to make more vampires?
shareMarcus made a bluff to keep Viktor from fully betraying him. Since he was the father of all vampires, he claimed that if he were to ever die, then all vampires will die with him. Viktor likely suspected that it was a bluff, but he probably wasn't ready to find out. He made the same claim for William to keep Viktor from killing him, that if he ever died, so would all werewolves, including the lycans who were still the vampires' slaves.
If nothing we do matters, then all that matters is what we do. -Angel