The warlocks of Azeroth are users of the highly destructive fel magic, which all titans (living worlds) were uniquely susceptible to. If the energies of disorder can obliterate living worlds and the living beings of those worlds, then the energies of disorder might destroy Azeroth. Its this highly destructive power that warlocks use in their incantations and rituals. These (spi)ritualists have the ability to make but an insignificant sacrifice -- a living necrolyte or two, a few strands of felweed -- to fuel fel magic. Sacrificial magic was considered the greatest violation of life and the titans had hounds, instantly attuned to punished those who delved into such sorcery, police the use of arcane magics.