Mdthbs

Maleficient is an evil witch on a quest for true immortality. Until she accomplishes her goal, she uses a midpoint form of magic called reincarnation in order to buy her more time and keep her alive. Reincarnation magic allows an individual to reincarnate themselves after death in the body of another human. Maleficient has a number of host bodies scattered throughout the world and trapped in a deep sleep to take control of in case she is killed by her enemies or dies of old age. Her most recent claim, a young girl named Snow White, is the next host that she will possess.

This spell takes a number of steps. After a person dies, their soul jumps into a magical item called a soul stone, which keeps the soul in storage and prevents it from crossing over to the next world. The soul is then transported and absorbed into the host body, giving the person possession over it. Reincarnation requires the victim to be living, so these hosts are placed in a coma-like sleep and kept in magical stasis to prevent them from aging. They are stored in this way until needed for further use.

The result is that the body now contains two souls within it that continue to remain separate, with the original soul remaining trapped and the dominant soul of the witch retaining control. The witch now has access to the person's memories, knowledge and spells to use. They can also access the person's mana for an extra boost in spellcasting if needed.

Powerful witches are likely to use this method to cheat death whenever possible, and limits need to be places on this form of magic to prevent constant overuse. In essence, individuals both weak and strong should only reincarnate themselves into others of their caliber. A witch might be powerful, but would have a hard time with this spell because there are few people walking around with that kind of power level. Alternatively, an average person would have an easier time because of a larger pool of individuals. However, this isn't a power grab. Even if they managed to take down a powerful opponent, transporting their own soul into them wouldn't be an option.

How can I accomplish this goal with these rules?

Remember analogue audio tapes? Copying them was a lossy process: If copied too often, you'd accumulate noise until the content is no longer enjoyable.

Make soul transfer a lossy process, too. Applied once, there's almost no change in the soul, but with each transfer, damage to the soul accumulates, until at some point it is too weak to take over the new body. It is still there, but the actual owner of the body is now in control, and can in turn make use of the witch's memories and powers.

1. Don't make the base witch inherently dominant. It should be a tough struggle of wills to take control of the new host. Of course, a skilled witch will be very skilled at soul combat, and have spells to pacify the other soul, but make it a struggle. The base soul is more suited for their body, so if they are trained in soul defense they may be the one who controls the body.




2. Make the souls an attractive target for any witch who wants power. The soul of a powerful witch, free of her body, could be a powerful ingredient in many spells, warding schemes, and potions that other witches could want. If you do die and anyone finds out, many witches will attempt to ambush and steal your soul. There's a strong incentive for whoever is managing the soul to sell it to any of many willing buyers.




3. Make soul transportation difficult. Losing your body and mastering the soul of another should be exhausting. During this time the witch is vulnerable to others stealing her secrets with mind magic, or being attacked.

Biological compatibility

As with organ transplants, the soul must be transplanted to a compatible body, in sufficiently good health that the shock won't kill them; else the transplantation process will fail. I would suspect that there wouldn't be too many people meeting the criteria, which is generally the case when looking for donors.

Secondly, the soulstone is a physical item, which needs time to be formed within the original body of the witch or within the host's body, so the witch can't just body hop whenever. Add on that the soulstone is a one shot: once the witch dies, the soulstone has to be physically transferred to the new host, where it will break down and transfer the soul into the host's body. Afterwards, the witch will have to generate a new soulstone for the next transfer, which would take a couple of years to do.

Loss of spell

What powers the spell is the spell itself: It unravels all memory of itself and how to get that knowledge, and uses that energy as a kickstarter. A clever witch will have given herself clues, left parts of it scattered around where only she can find or understand it, but finding the spell again will take time. Writing it down where everyone can find it, will be too dangerous, since she is not able to defend herself once in the stone, so it must be hidden cleverly. Most people only manage it once. They die, having spent their priceless, second life frantically searching without success.

I can think of a few ways. First, soul stones could be hard to make and degrade with each transfer to a new host body. The chances of it failing to retain the soul during the transfer go up each time it’s done. Thus, the witch risks crossing over to the afterlife more. And making a new soul stone can’t be done without potentially breaking the artificial attachment to the new host body.

Second, with each transfer, the pool of compatible hosts decreases. You absorb traits from each host body, which means the list of traits you have to match gets longer. That increases the difficulty finding potential hosts.

Third, potential insanity. Your soul might have an allergic reaction to the host body, causing you to gradually lose your mind.

Why invent anything different that plain old high mana/ingridients cost? The spell is so complex, that it requires a lot of magical energy stored up. Collecting it in such amount is difficult and takes years by performing (insert a list of non-trivial time and effort consuming tasks). Unless witch fails to complete this preparation in time for next cast it is game over for her. And if there are people working on killing her, "in time" might come quite quick and unexpected.