Mfcttrf

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 keeps a number of host bodies trapped in a deep sleep to take control of in case she is killed by her enemies or dies of old age.

These bodies are stored together in a secret dungeon only she can get to, away from prying eyes and kept safe in stasis. However, while this magically induced sleep keeps the individual alive in stasis, it presents a problem to her. Muscle atrophy is defined as a decrease in the mass of the muscle; it can be a partial or complete wasting away of muscle, and is most commonly experienced when persons suffer temporary disabling circumstances such as being restricted in movement and/or confined to bed as when hospitalized.

This means that even if the spell is successful, the witch would be completely handicapped. This would make keeping these bodies stored useless as she would be completely crippled.

How can she overcome this problem? What other issues am I likely to face with preserving the victim with this spell?

Time Magic

If you're using a stasis spell anyway, just make the stasis spell a fourth-dimensional one rather than a third-dimensional one, i.e. the spell traps you in time, rather than space. No muscle atrophy.

Healing Magic

The spell uses healing magic to prevent muscle atrophy. Elegant and simple.

Exercise Magic

Similar to real-life coma patients, a spell can be created that will artificially move them, possibly using Range Of Motion exercises or something similar to keep the body in a state of basic use. Magic will be needed to provide the energy for this reaction.

Combine the stasis with a magically induced neuromuscular electrical stimulation.

This is a potential method to protect people in cryostasis from atrophy during long-distance space flights. This article mentioning it is an interesting read in this context altogether.

Another problem your facing is that of nutrition, and the general biological functions of the body.

The best option might be to induce a mind-numbing zombie-like state, in which these husks have been instructed to follow a simple predetermined daily pattern of exercise, eating, and sleeping.

Their original personality might have been completely 'wiped out', and their consciousness suppressed sufficiently, so no sudden surge of existential anxiety or similar unwanted reflective behaviour occurs - mostly to prevent psychosomatic or self-inflicted damage.

Freeze them in time.

If time is magically stopped for the would be host, then not only wouldn't their muscles atrophy, but there would be a few other benefits, too.

For example, they wouldn't age, either. Nor would they need to eat/be fed. Or breathe, even.

Time Magic, the perfect preservative. Well, almost perfect. Depending on how the magic interacts with its unfrozen surroundings, there could be some problems.

Do heat and light get reflected? If not, and they act normally, then the subject would be visible, but it wouldn't be producing heat. Waking up at room temperature wouldn't be great, though I'm not certain the exact problems it causes for the human body.

On the other hand, if heat and light merely stopped when they hit the edge of the magic, then they'd build up, and when time was unfrozen, the subject could be flash fried. Also, the subject wouldn't be visible while frozen. They'd appear as the darkest black, stopping all light.

To protect the subject from the elements, if they don't wish to make the subjects reflect light and heat, I'd suggest freezing them outside of time and space. Might need to open a portal to a pocket dimension, or something. But, at least it'd be more dramatic than merely poisoning someone.

The husks are possessed.

Summoned spirits animate the husks. It is added value; these spirits have their own abilities and are useful associates in their own right but they need somewhere to inhabit while on this plane or it is difficult to get any work out of them. Having them live in the reincarnation husks gets use out of these bodies. The spirits keep them fed and fit. Plus these husks are easy on the eye (of course!) and it is good for morale to see them up and about.

A problem arises when the spirits have their own agendas and make use of the bodies which are not in line with Maleficents ultimate goals for these bodies. Or, very occasionally, fluctuation in a spirits mana allows the host to awaken and take control, now with a spirit as her prisoner within her body.

Templates and triggers

The witch, an engineer as she is, have magically turned the bodies to crystal along with a 'rebuild me'-spell along with an active spirit-link. Upon her death, the connection is broken, and the spell is triggered to activate.

As her brain shuts down, the crystal start compiling data and reconfigures her body, mind and soul within the husk before exploding in a fiery blaze, leaving her quivering and naked on the cool floor.

She opens her eyes, muttering "toadstool and crickets, not again..."

It's just more magic. If magic made them sleep, it probably solved the other problems. The suspension of belief is already there.

From a reader's point of view (at least if I'm the reader), I don't think the concept of muscle atrophy would present itself to me as a logical problem with a coma/statis spell. When reading about sleeping beauty or Rip Van Winkle growing up, I don't think that thought ever occurred to me. Moreover, the reader is probably already familiar with the concept of sleep spells in a fantasy setting from other stories, so the expectation would be that that's not an issue (as opposed to stasis chambers in sci-fi where muscle degeneration is a commonly-discussed issue).

Also, IMHO, as a reader I think I might find it distracting if the narration tried to explain the details of something like that if I didn't think it needed explanation, though I suppose it depends on the kind of story it is and how the explanation was done.

I guess all of this is assuming this is for a story-telling purpose. Maybe from a more literal worldbuilding point of view my thoughts would be less relevant.