#lich's mastery

Lich’s Mastery (9th Level, Necromancy)

Casting Time: 8 hours (ritual)

Range: Self

Components: V, S, M (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

 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 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. 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.

Just one.

Even though you share a life total with your teammate in 2HG, you both gain and lose life separately with the result applied to the shared life total. Your teammate gaining or losing life won’t trigger Lich’s Mastery.

A few other notes on 2HG and Lich’s Mastery:

Hexproof only applies to your opponents. Your teammate can target Lich’s Mastery if they want to.

As long as you control Lich’s Mastery, your teammate can’t lose the game either.

When combat damage is dealt to your team, the creature’s controller chooses which member of your team the damage is dealt to. They probably want to deal it to the player with Lich’s Mastery.

When the game gets to the point where your opponent has to have Teferi tuck itself each turn in order for them to not deck out, the game has entered a loop and your opponent will have to make a different decision, i.e. not tuck Teferi, to not continue the loop.

TL;DR: Your opponent has to stop their loop, so you win.

You don’t lose the game and the game continues.

If you have Gideon of the Trials’s emblem and control a Gideon planeswalker, then you won’t lose the game when Lich’s Mastery’s last ability resolves. The trigger will try to make you lose the game, but you can’t lose the game and so nothing happens and the game continues.

Yes.

When you gain 7 life from Approach of the Second Sun, Lich’s Mastery will trigger. When that trigger resolves, you’ll draw 7 cards. Unless something weird has happened, the last card you draw will be the Approach of the Second Sun that you just cast.