Leviathan blood is blood from Leviathans and Leviathan hybrids. It can be produced by Leviathan vessels and Hybrid Leviathan vessels by infecting the human's blood, as well as Leviathans in their true form. It's black and is extremely poisonous and toxic to humans, monsters, demons and angels. It's unknown if Leviathan blood gives humans powers like demon blood gives special children powers or if it can be used in spells. Leviathan blood can be drawn by normal weapons like guns and knives, but can't kill them.