Lich’s Mastery

As you cast this spell, you perform a ritual that slowly enmeshes your soul with the one that you’ve trapped, entwining them together into the iron, which shapes itself into a suit of armor made for you and bound forever to your skin. After casting this spell, you become an undead creature, and you no longer need to breathe, drink, eat, or sleep. You are immune to necrotic and poison damage, can not be diseased or poisoned, and can not suffer exhaustion except as a result of this spell. The magical iron binds itself to your skin in a highly painful process, becoming a suit of armor. You can not remove this armor, and while wearing it your AC is 17 and you have an advantage on saving throws against spells and other magical effects. The armor has a number of hit points equal to your maximum hit points at the time you cast the spell, and whenever you would take damage, the armor takes that damage instead. Damage to the armor manifests as pieces of iron chipping off and falling to the ground, at which point they vanish into black dust. To repair the armor and restore its hit points, you must perform a magical ritual that takes 8 hours to complete, requires you to expend a 9th-level spell slot, and costs a number of gp equal to 10 x the number of hit points being restored to the armor. If the armor is reduced to 0 hit points it shatters, leaving behind only a few scraps attached to your body, and you must make a DC 20 Constitution saving throw. On a failed save, you are reduced to 0 hit points and begin dying, and automatically fail any death saving throws. On a success, you instead take 4d10 necrotic damage and suffer one level of exhaustion, which can not be removed by taking a long rest. At the end of each long rest that the armor remains broken and unrepaired, you must make another Constitution saving throw, with the same results. In addition to the normal costs, repairing the armor once it has been reduced to 0 hit points also requires the soul of another humanoid trapped using soul cage or another method, which is expended in the process of repairing the armor.
Legendary Spell You must be 20th level or above in order to cast this spell.

9th Level	Necromancy
Casting Time	8 hours (ritual)
Range	Self
Components	Vocal	Somatic	Material (the soul of a humanoid trapped using soul cage or some similar method and 5000 GP worth of magical black iron, both consumed in the casting)
Duration	Instantaneous
Classes	Cleric	Warlock	Wizard

Lich’s Mastery

Effect

After casting this spell, you become an undead creature, and you no longer need to breathe, drink, eat, or sleep. You are immune to necrotic and poison damage, can not be diseased or poisoned, and can not suffer exhaustion except as a result of this spell.

Side/Secondary Effects

The magical iron binds itself to your skin in a highly painful process, becoming a suit of armor. You can not remove this armor, and while wearing it your AC is 17 and you have advantage on saving throws against spells and other magical effects. The armor has a number of hit points equal to your maximum hit points at the time you cast the spell, and whenever you would take damage, the armor takes that damage instead. Damage to the armor manifests as pieces of the iron chipping off and falling to the ground, at which point they vanish into black dust.

Manifestation

After casting this spell, you become an undead creature

Source

Class	Source
Cleric	Deity
Warlock	Patron
Wizard	Added to spell repertoire each morning

Material Components

the soul of a humanoid trapped using soul cage or some similar method and 5000 gp worth of magical black iron, both consumed in the casting

Gestures & Ritual

As you cast this spell, you perform a ritual that slowly enmeshes your soul with the one that you’ve trapped, entwining them together into the iron, which shapes itself into a suit of armor made for you and bound forever to your skin.

Related School

Necromancy

Effect Duration

Instantaneous

Effect Casting Time

8 hours (ritual)

Range

Self

Level

9th