Magic Resistance. The archmage has advantage on saving throws against spells and other magical effects. If a spell cast at it has a spell level of 7 or lower, the Zenither automatically succeeds.

Undying. If the Zenither is reduced to 0 hit points, it retreats to a private demiplane that cannot be endangered without direct influence from a God. There, it regains 1 hit point immediately plus 100 more each half hour. If it is slain inside of its demiplane, it dies.

Adamant Endurance. Whenever the Zenither or its Deva avatar takes less than 20 damage from a single attack or spell, it takes no damage instead unless that damage was dealt by magic equal to or greater than a level 9 spell.

12000 Foot Sense. The Zenither has truesight of 12000 feet (about 2.27 miles or 3.66 kilometers). Within this range, the Zenither can see through walls, hear, smell taste, and feel anything within the 12000 foot range. The Zenither can also see through magical darkness within this range and barriers that magically stop the senses, unless caused by a level 6 or higher spell.

Withering Wave. The Zenither choose up to 3 targets that it can see within 120 feet of it to take 85 (10d10 + 30) force damage. Alternatively, this damage can be replaced with necrotic or cold damage. Any humanoid, beast, fey, or celestial killed by this turns into a Wraith with an Intelligence stat equal to the humanoids stat minus 8, to a minimum of 3. These Wraiths don't remember any languages or anything about their past lives. Alternatively, they become a Ghast if that better matches their level of power.

Zenith Display. The Zenither make 1 display of power from the list below. When the Zenither uses a Zenith Display, it cannot use the same one until after 2 others have been used. If the Zenither uses the same Zenith Display more than 2 times per day, it takes 23 (2d12 + 10) force damage from the effort each additional time it uses that display.

• Deva Avatar. The Zenither summons a Deva under their control. This is not a real Deva, but a necrotic avatar of the Zenither that shares the Zenither's knowledge. The Deva's turn directly follows the Zenither's. All radiant damage dealt by the Deva is necrotic instead, and they are immune to necrotic damage. The Zenither can have 1 Deva under its control at a time, and the Deva vanishes if it's more than 12000 feet from the Zenither or if it or the Zenither is reduced to 0 hit points.
• Eternal Torment. The Zenither telepathically speaks words of pure chaos. Every creature (besides the Zenither and the Deva avatar) within 120 feet of the Zenither must succeed in a DC 23 Wisdom saving throw or be mentally infected. A creature who is mentally infected can heal themselves through any healing spell of level 7 or higher, or similar magic. Until cured, mentally infected creatures have an alignment 1 step closer to Chaotic Evil (lawful and good become neutral, and neutral becomes chaotic and evil. Example: Neutral good becomes Chaotic Neutral) and they also take 1 psychic damage every half hour for the rest of their life unless they are immune to it. If they are reduced to 0 hit points by this they die.
• Ethereal Sea. The Zenither creates a sea of black cosmic fluid within 12000 feet of it. The fluid has the consistency of thick gel and can take any shape, but it must be no more than 1000 feet long in any dimension, and no part of it can be created over 12000 feet away from the Zenither. Creatures inside it must make a DC 16 Strength Save to be able to move, where they can move up to half their swimming speed rounded down to the nearest 5 feet, and they are unable to move if they have no swimming speed. Creatures who start their turn touching this fluid must succeed in a DC 17 Constitution saving throw or take 16 (3d8 + 3) cold damage. This effect applies to the Deva Avatar but has no effect on the Zenither. At the start of each turn, the Ethereal Fluid shrinks up to 100 feet in all dimensions on all parts that are over 12000 feet from the Zenither.
• Fiendish Vibrations. An explosion of deadly vibrations affects everything (including the Deva Avatar) within 1000 feet of the Zenither, except the Zenither itself and the ethereal fluid created by it. This deals 135 (10d20 + 30) fire damage to all creatures that fail a DC 27 Constitution saving throw, and half damage on a successful one. This can shred through 200 feet of dirt, 150 feet of wood, 50 feet of stone, 10 feet of any metal, and 6 inches of adamantine. All armor hit by this has a -1 to its armor class (not stackable, minimum of 10). After the Zenithar uses this, it takes 36 (4d12 + 10) force damage from the effort.
• Space Warp. The Zenither teleports up to 100 miles away. Alternatively, it may go directly to a different plane of existence. It can teleport from one inner plane to another or one outer plane to another. To teleport from an inner to an outer plane, it must spend 10 minutes performing a ritual with somatic components.
• Fear Ring. The Zenither chooses up to 20 creatures it can see within 12000 feet of it. Those creatures must succeed in a DC 21 Wisdom saving throw or be frightened of the Zenither until the end of a long rest.
• Abyssal Item. The Zenither uses 7 magic touches on 1 or more weapons. Each touch on the weapon increases the necrotic damage it deals per turn by 1d10 and gives it a +1 bonus to attack and damage rolls. No weapon can exceed a +7 bonus and 7d10 necrotic damage in this way. If the Zenither dies, the weapons are unaffected other than losing 1d10 of the necrotic damage bonus.
• Shifting. The Zenither moves an object that weighs less than 10 tons and is within 500 feet of it up to 100 feet.
• Divine Shield. The Zenither gains a number of temporary hit points equal to half the amount of damage it currently has on it.

Counter. Every time a spell of level 4 or lower is cast within 12000 feet of the Zenither, it can choose to negate its effects for free. It can also negate level 5 to 8 spells using Counter Points. It regains 5 counter points at the start of each of its turns, to a maximum of 20 counter points. Negating level 5 spells costs 1 point, level 6 costs 2, level 7 costs 4, and level 8 costs 8.

God's Immunity. The Zenither is immune to all conditions. Once per round when an effect is applied that would cause the Zenither to have a condition upon failing a saving throw, the Zenither can choose to make that saving throw. If the Zenither fails that saving throw, it may choose a creature it can see within 120 feet of it to give that condition to, unless the condition is charmed, frightened, grappled, restrained, or invisible.