Multifaceted. When targeted with an effect or spell, Zachary can choose to count as a Celestial, Undead, Humanoid, or Monstrosity. For example, if targeted with turn undead, he could choose to be counted as a monstrosity and be immune to the effect, or when attacking a creature with protection from evil and good, he can choose to be counted as a humanoid.

Molded by the Void. Zachary is voidtouched. He suffers no penalties from being in the void and half void. He cannot forcibly have his form changed, and he can fit through spaces as small as 1 foot in diameter. When grappled, he can escape immediately at the start of his turn (no action required).

Fool Me Twice. When Zachary makes a saving throw, he can choose to fail. When he fails a saving throw this way, he, from then on, immediately succeeds when subjected to it again. This resets after a long rest.

Ongoing Hatred. When Zachary takes more than 50 damage in one turn, he gains 25 temporary HP, and may use his sneak attack twice on his next turn. When he takes more than 100 damage, he gains 25 more temporary HP and gains an additional action on his next turn.

Reckless Outburst. When he misses an attack or a creature succeeds a saving throw he forces them to make, his next attack he makes is with disadvantage, or the next creature he forces to make a save does so with advantage, however if he hits or the creature fails, the damage is calculated as a critical hit.

Voidborne. All of Zachary's attacks count as magical for the purposes of overcoming resistances and immunities.

Sneak Attack. Once per turn, when he deals damage to a creature, Zachary can deal an additional 28 (8d6) Force Damage.

Spellcasting. Zachary is a 15th level spellcaster. His spellcasting ability is charisma, and his spell save DC is 22, with a +14 bonus to spell attack roll. He has the following spells prepared:

Cantrips: Toll the Dead, Thaumaturgy, Eldritch Blast, Mage Hand, Plane Shift

At will: Haste, false life (5th level version), Misty Step, Hungering Blade, Plane Shift, Black Ribbons

2/Day each: Revivify, Danse Macabre, Bane, Black Tentacles, Eyebite

1/Day: Finger of Death, Divine Word

Eldritch Revenant. When You've Done It Now triggers, Zachary gains the following benefits:

• Zachary's speed increases by 30 feet.
• Zachary gains resistance to piercing, bludgeoning, and slashing damage.
• Zachary's strength score becomes 30. 

Multiattack. Zachary makes 3 attacks with the Eldritch Blade, or when possible, gut attacks.

Eldritch Blade. Melee Weapon Attack: +15 to hit, reach 5 ft., 1 target. Hit: 18 (4d4 + 8) Piercing damage + 26 (4d12) Necrotic damage.

Underhand Stab (recharge 4-6). A creature within 5 ft of Zachary must make a DC 23 Dexterity saving throw. On a failure, a creature takes 55 (10d10) piercing damage + 29 (5d10) slashing damage as they get stabbed by Zachary with a quick gut strike which he then drags upward through their body. The creature then falls prone, and is incapacitated until they gain at least 25 points of healing, which ends this effect. At the end of each of their turns, they take 9 (2d8) necrotic damage as they bleed out slowly. On a success, a creature takes no damage and suffers no effects. A creature that fails this save cannot be targeted with this action for the rest of this combat.

Gut. Zachary deals 33 (6d10) slashing damage to a creature that is restrained, prone, or grappled by him. 

Tag. Zachary forces one creature within 60 ft. Of him to make a DC 22 CON saving throw. On a failure, both him and the creature are transported to the half void. If a creature fails by 5 or more, they fall unconscious for 1 minute or until they take damage from oxygen deprivation by the harsh conditions of the half void. 

Cunning Action. Zachary takes the dash, disengage, or hide action.

Watch Your Step. When a creature misses Zachary with a melee attack, Zachary can use a reaction to sidestep and trip the person, moving 5 feet without provoking oppurtunity attacks and choosing to either:

• Force the creature to reroll the attack against another creature within 5 feet of Zachary
• Make the creature fall prone

You've Done It Now. When reduced to 0 hp, Zachary dies for one round. He then rises again at the start of his next turn at full health, enabling his Eldritch Revenant traits and unlocking a new action:

Rampage (5-6). Zachary makes an Eldritch Blade attack towards a creature. If it hits, he may make another. This can happen up to ten times. If he reduces a creature to 0 hp with this attack, he may move up to his speed and use this action again (up to three times).