A group of shamans are trying to banish an immortal witch so she can no longer use her magic to commit dark seeds. Objects like statues are too weak to contain her soul so they must resort to beings of flesh, so they turn to farm animals. However the animals they try to banish her to are too weak and die, sheep, goats, cows and horses. All except one, a steer. After a very lengthy ritual which involves a lot of witch screeching and bellowing, the steer lives and the witch is now bound within its bones. I need help thinking of a good explanation why a steer can contain a witch's soul as opposed to say, a horse for example. Can you help me? FYI - A steer is a young castrated bull.
Castration makes animals more docile. Perhaps it needed to be a large and powerful animal (you wouldn't try and lock Nyarlathotep in the body of a hamster, would you?) physically, but anything like that might have enough sheer willpower to cast the demon out, or at least put the issue in doubt. Not sure why you couldn't use a gelding instead, but a powerful animal that has literally had its balls cut off might be a good vessel.
OP said "bound within its bones" so I'm guessing they go off to be made into wands at whatever shop that was in the Potterverse
You could make it so that there is something special about this steer in particular, not just that it's a powerful animal. It was born pure (Whatever color) which is a symbol of a powerful spirit or god, or has a birthmark that is reminiscent of a symbol of a spirit or god. It was born on a spiritually important date or during an unusual natural phenomenon like an eclipse. It has been attacked by wolves, hit by arrows, bitten by snakes, whatever, and survived. Bonus if it was attacked 3 times. The steer was a gift from a mysterious figure. Perhaps the owner helped that mysterious figure out and he granted her a boon.
I think the question was more about what happens to the witch when the steer dies? I also tend toward the idea that if there are shaman(s), then the magical woman would probably be called a sorceress rather than a witch. A shaman who becomes stronger and starts working evil and working against evil to protect people (selling his services) was called a sorcerer. I'm also not quite sure how you'd work in the explanation of why one animal works while others didn't since it seems the shamans themselves don't know. Who would have the answer, and if they knew, then why did the shamans have to experiment several times before finding the right animal? Unless they work out some theoretical idea of why this one worked while the rest didn't. Unless its simply the fact that the other animals weren't strong enough, and they had to keep trying until they found one that was.
