Destroying the Enchanted Device
Keeping the enchanted device that empowers the living corpse intact is of prime importance. According to the Damaged Goods rules in City & Guild, pages 77–79, an item that is physically damaged must make a Stress Check to avoid losing Damage Levels, which operate much like Fatigue Levels. Hermetically enchanted items have a bonus to this check, equal to the total number of magnitudes invested in them.
When the enchanted device is threatened with physical harm, the player rolls a Stress Check to avoid losing a Damage Level. Whatever actual shape the enchanted device takes, it has 5 Damage Levels, based on the Item Quality (Supernatural) and its Size (–5 to +1).
Stress Check: stress die + modifier vs. 15
A damaged enchanted device can be repaired only by a Verditius magus who knows the Minor House Mystery Virtue: Reforging Enchanted Items (Houses of Hermes: Mystery Cults, page 125). It seems logical that a destroyed enchanted device, whose destruction signals the end of the living corpse character, could be put back together and, once so reforged, would again create the living corpse.
know he is undead and may treat him as they always have.
A living corpse gains a host of new advantages — primarily that he no longer has to fear the ravages of time. But new concerns become paramount, and just as many disadvantages come along with the benefits.
Advantages
The primary advantage of becoming a living corpse is eternal life. The living corpse does not eat, sleep, or even breathe, and is immune to aging. The player no longer has to make annual Aging rolls for the character. Affiliated with the Magic realm — or one of the other supernatural realms — a living corpse is immune to Warping and Final Twilight. As long as the magic that holds the living corpse together persists, the entity exists.
Physical afflictions are a thing of the past. A living corpse is not as hindered by damage and disease as living things. Physical wounds still provide a penalty for physical activities, but the living corpse cannot be Incapacitated. He literally needs to be hacked to bits to be destroyed, but even dismemberment can be remedied. A disease still inflicts a Disease Penalty (see Art & Academe, page 45), but this only reduces physical rolls that the damaged corpse must make. Die rolls that the ghost half of the living corpse character makes are not affected, examples being Lore, Folk Ken, and other mental or social Ability rolls. A living corpse can ignore the rules for Activities While Wounded (ArM5, page 178).
If your troupe is using the Wealth and Poverty rules from Covenants (pages 56–70), a living corpse costs 0 points of inhabitants. Although still living in his sanctum and laboratory, a living corpse cannot undertake Hermetic lab work. His lab needs to be financially maintained if he is keeping up the façade of a living magus, though, using materials and supplies and making the covenant pay for them. This cost isn't mandatory, but if the magus stops buying candles and parchment, the covenant's staff and magi may become suspicious.
Disadvantages
The two biggest concerns of a living corpse are its vessel, which must be preserved and protected, and the enchanted device that holds the living corpse together. It is debatable which is more important, for the destruction of either causes the living corpse to disassemble. Constant protection of the two are the order of the day, and a living corpse who ignores sound precautions will not be a living corpse for long.
For the combined spirit-corpse to properly function, the vessel must be kept whole. If the living corpse is unlucky enough to have the entire corpse as the ghost's vessel, he should shy from any activity that could damage the body. The ghost cannot voluntarily leave its vessel unless it has Powers that it can use to temporarily bind to a different vessel. If the vessel is substandard, attaching to a second is not easy. If the fleshy vessel is permanently destroyed, the character is merely the ghost of a magus. What happens next is up to the storyguide and the troupe, although in most cases the ghost will depart. A storyguide may allow a player to have a ghost character, but in most cases the ghost is whisked to the supernatural realm it is affiliated with, and removed from play.
Protecting the enchanted item or items is equally as vital as protecting the vessel. If the item is destroyed, the body collapses, the ghost cannot control it, and the ghost is no longer bound to it. Perdo Vim magic that cancels the magic without destroying the device can also bring ruin upon the living corpse. As soon as the ghost is unbound from the vessel, either because the vessel is broken or the magic that connects the two ends, the ghost departs. If the Perdo Vim magic that canceled the enchanted item's effects is not permanent, the enchanted item might activate its spell-like effects if the linking triggers' conditions are met. However, the ghost is most likely not in proximity, and the enchanted item will not be able to target the ghost.
Ghosts themselves are susceptible to

Perdo Vim magic that destroys Might, and the living corpse is no exception. Might destroyed by Perdo Vim spells is permanently lost, and the living corpse also loses Qualities equal to the number of lost points, further decreasing its power. If the living corpse's Magic Might is reduced to 0 through Perdo Vim spells, the ghost is permanently destroyed, erased from the supernatural fabric of Mythic Europe.
Rego Vim and Rego Mentem spells are also problematic, although not as dangerous as Perdo Vim spells. Rego Vim and Rego Mentem wards prevent a living corpse from entering (or exiting), provided the spells are strong enough and carry enough Penetration to affect the living corpse. Because a living corpse is a combination of ghost and corpse, Mentem spells that summon and bind a ghost are also a threat. It is possible that a Rego Mentem spell more powerful than the one initially used to bind the spirit could control a living corpse.
Death severs the magus-familiar