6 decades books

All living things have needs that must be met if they desire their life to continue. Such needs range from the universal requirement for sustenance, to the more specific, such as the requirement of all higher life to sleep, or even the esoteric, such as the requirement of a pain demon to inflict suffering. The ability to exploit those needs is what separates, to pick a random example, a successful summoner from the shrivelled (but very happy) corpse that had, a few minutes earlier, conjured up a succubus with no plan of how to control her.