In ‘Stones in the Sea,’ I gave some details on the fact that a powerful sorcerer could enter and control the minds of some lower animals — essentially those without much (or no) sense of self. The goddess Kesarra demonstrates this ability with sea snakes, spiders, and such. Although she can touch sometimes their thoughts, she is incapable of controlling more advanced creatures; whales, for example. Certainly not humans!
I had hinted at this idea in much earlier books. Notably, another goddess, Mawa, used spiders to ‘see’ what was going on elsewhere in ‘The Crocodile’s Son.’
Now another mind that no longer lacks consciousness would be that of a newly deceased person. A sorcerer with the ability can control that mind and its body. This is, in essence, a zombie, as defined in my Izan fantasy stories. I first introduced the concept in the novel ‘Valley of Visions,’ where the warlord Ko is resurrected to harangue his troops into action, with the mad wizard Teshum pulling his strings.
Pretty much everyone, including gods and other sorcerers, strongly condemn such abuse of wizardly powers, as well as recognizing its dangers. It is possible for the wizard controlling a body to become trapped there (at least temporarily) as it deteriorates. Yet some will use such ‘magic’ anyway. It reappears in ‘The Plain of Silver,’ when a zombie assassin is sent to attack a princess of Sharsh (essentially to stir up war).
This is a theme best used infrequently. By positing the need for extraordinary sorcerous power, I can and do limit it. I also limit its effectiveness, to make it less attractive an option for wizards. There is a relatively narrow window of opportunity for seizing control of a dead man’s brain. The body itself will deteriorate and become less useful and harder to control.
On whole, one is better off sticking to spiders.