Archlich

Legendary Resistance (3/Day). If the archlich fails a saving throw, it can choose to succeed instead.

Rejuvenation. If it has a phylactery, a destroyed archlich gains a new body in d10 days, regaining all its hit points and becoming active again. The new body appears within 5 feet of the phylactery.

Spellcasting. The archlich is a 20th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 23, +15 to hit with spell attacks). The lich has the following wizard spells prepared:

     Cantrips (at will): mage hand, ray of frost, shocking grasp
     1st level (at will): detect magic, magic missile, shield
     2nd level (at will): arcane lock, detect thoughts, invisibility, mirror image
     3rd level (at will): animate dead, counterspell, dispel magic, fireball
     4th level (3 slots): blight, ice storm, phantasmal killer
     5th level (3 slots): cloudkill, hold monster, wall of force
     6th level (3 slots): chain lightning, circle of death, disintegrate
     7th level (3 slots): finger of death, plane shift, teleport
     8th level (2 slots): maze, mind blank
     9th level (2 slots): power word kill, time stop

Turn Resistance. The archlich has advantage on saving throws against any effect that turns undead

Soul Leech

The Archlich has a malevolent connection to the souls of those it defeats. Whenever it delivers the killing blow to a creature, it can choose to leech its soul. 

When the Archlich uses this ability, it absorbs the soul of the fallen creature, preventing it from being resurrected by any means short of a Wish spell. For each soul it absorbs, the Archlich gains temporary hit points equal to the creature's maximum hit points. These temporary hit points last until the end of its next long rest. The Archlich can hold a maximum of three absorbed souls at a time. If it absorbs more than three souls, it must release one to make room for the new soul. The released soul is freed and can move on to the afterlife.

Paralyzing Touch. Melee Spell Attack: +12 to hit, reach 5 ft., one creature. Hit: 10 (3d6) cold damage. The target must succeed on a DC 18 Constitution saving throw or be paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Shadow Walk (Recharge 5-6): The Archlich possesses an innate connection to the shadows, allowing it to navigate the darkest reaches of the ethereal plane. When the Archlich uses its Shadow Walk ability, it melds with the shadows around it, enabling it to traverse the ethereal realm for a brief duration.

• Activation: As a bonus action, the Archlich can activate its Shadow Walk ability. When it does so, its form becomes insubstantial and shadowy, and it gains the following benefits for 1 minute:

  • Ethereal Movement: While in Shadow Walk, the Archlich can move freely through solid objects and creatures as if they were difficult terrain. It doesn't take damage or cause harm when passing through objects or creatures, but it cannot end its turn inside them.

  • Invisibility: The Archlich becomes invisible to creatures on the Material Plane. It can see and hear the Material Plane as if it were adjacent to it, but creatures on the Material Plane can't perceive the Archlich unless they have the ability to see invisible creatures or use magic to reveal it.

  • Shadow Step: Once during its turn, the Archlich can use a bonus action to teleport to an unoccupied space it can see within 60 feet on the Material Plane or the Ethereal Plane.

• Interdimensional Tactics: While in the ethereal realm, the Archlich gains advantage on Dexterity saving throws and can avoid many physical obstacles that would hinder its movement on the Material Plane. The Archlich's walking speed is also tripled to 90ft for the duration of the ability. It uses this advantage to reposition strategically during combat or to evade attacks.

• Recharge: After using Shadow Walk, the Archlich must wait until it rolls a 5 or 6 on a d6 at the start of its turn to regain the ability to use Shadow Walk again. Once recharged, it can use this ability once more.

1. Command Undead (Recharge 5-6): As a bonus action, the Archlich can attempt to exert its control over an undead creature it can see within 60 feet. The target must make a Wisdom saving throw (DC 17) or be charmed by the Archlich for 1 minute. The charmed creature follows the Archlich's commands to the best of its ability, and it can repeat the saving throw at the end of each of its turns to end the effect.

2. Arcane Shield: As a bonus action, the Archlich can conjure an arcane shield around itself. This shield grants the Archlich temporary hit points equal to 1d10 + its Intelligence modifier (minimum 1). These temporary hit points last for 1 minute or until depleted.

3. Dark Aura (Recharge 6): The Archlich can activate a dark aura as a bonus action. Creatures within 10 feet of the Archlich at the start of their turn take 2d6 necrotic damage. A Constitution saving throw (DC 17) halves the damage. The aura persists for 1 minute or until the Archlich uses this ability again.

4. Life Drain: As a bonus action, the Archlich can make a melee spell attack against a creature it can reach. On a hit, the target takes 2d8 necrotic damage, and the Archlich regains hit points equal to half the damage dealt.

5. Teleportation: As a bonus action, the Archlich can magically teleport to an unoccupied space it can see within 60 feet.

6. Counterspell (Recharge 5-6): The Archlich can use a bonus action to prepare a counterspell. When a spell is cast within 60 feet of the Archlich, it can use its reaction to make a spellcasting ability check (DC 10 + the spell's level). On a success, the spell is countered.

7. Mystic Resonance: As a bonus action, the Archlich can infuse its spells with dark energy. For the next minute, all of the Archlich's spell attacks have advantage, and creatures have disadvantage on saving throws against its spells.

8. Summon Undead (Recharge 6): The Archlich summons an undead minion to its side. Roll a d4 to determine the type of minion summoned: 1:Skeleton, 2:Zombie, 3:Wraith, 4:Specter. The summoned undead appears within 30 feet of the Archlich and acts on the Archlich's initiative count. It remains for 1 minute or until destroyed.

    

1. Arcane Deflection (Recharge 5-6): When the Archlich is targeted by a spell that requires a saving throw, it can use its reaction to attempt to absorb the incoming magic. The Archlich makes an Intelligence saving throw with a DC equal to the spell's save DC. On a success, the Archlich takes no damage and gains temporary hit points equal to half the spell's damage. On a failure, it takes full damage.

2. Soul Ward: When the Archlich is reduced to 0 hit points, it can use its reaction to invoke its phylactery's protective magic. The Archlich is instead reduced to 1 hit point and is immune to damage and effects for 1 round. During this round, it can't take any actions or reactions.

3. Countercurse (Recharge 6): When the Archlich is targeted by a spell, it can use its reaction to attempt to turn the magic against the caster. The Archlich makes an Intelligence saving throw with a DC equal to the spell's save DC. On a success, the spell's effects are reversed and affect the caster instead. On a failure, the spell proceeds as normal.

4. Necrotic Ward: When the Archlich takes damage from a melee attack, it can use its reaction to retaliate with necrotic energy. The attacker takes necrotic damage equal to half the damage it dealt to the Archlich.

5. Death's Grasp: When a creature within 30 feet of the Archlich is reduced to 0 hit points, it can use its reaction to attempt to capture the soul of the dying creature. The creature must make a DC 15 Constitution saving throw. On a failure, its soul is trapped, preventing resurrection. The Archlich can release the soul at its discretion.

    

6. Undead Servitude: When a creature within 60 feet of the Archlich dies, it can use its reaction to raise the creature as an undead minion under its control. The type of undead minion depends on the creature's Hit Dice: 1-4 HD: Zombie, 5-8 HD: Skeleton, 9-12 HD: Wight, 13+ HD: Specter. The raised undead acts immediately, following the Archlich's commands.

The archlich can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The archlich regains spent legendary actions at the start of its turn.

At-will spell. The archlich casts one of its at-will spells.

Paralyzing Touch. The archlich uses its Paralyzing Touch.

Summon Undead. The Archlich uses it's Summon Undead ability.

Frightening Gaze (Costs 2 Actions). The archlich fixes its gaze on one creature it can see within 10 feet of it. The target must succeed on a DC 20 Wisdom saving throw against this magic or become frightened for 1 minute. The frightened target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a target's saving throw is successful or the effect ends for it, the target is immune to the archlich's gaze for the next 24 hours.

Disrupt Life (Costs 3 Actions). Each non-undead creature within 20 feet of the archlich must make a DC 20 Constitution saving throw against this magic, taking 42 (12d6) necrotic damage on a failed save, or half as much damage on a successful one.

Lich's Wrath.

As a legendary Archlich, the creature can tap into ancient and cataclysmic powers, invoking the wrath of dark gods or cosmic forces. The Archlich can use this mythic action at the end of another creature's turn, taking the initiative count of 20 (losing ties) on the initiative order. It can use the Lich's Wrath ability once per day.

The Archlich raises its bony hand, and a swirling vortex of necrotic energy forms above it, crackling with malevolent power. The Archlich then directs this energy at a target of its choice within 120 feet. The target must make a Dexterity saving throw with a DC of 18. On a failed save, the target takes 8d10 necrotic damage and is paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the paralysis on a success.

Additionally, any undead creatures within 30 feet of the initial target are bolstered by the dark energies and gain temporary hit points equal to half the necrotic damage dealt.

Soul Reaver

As a legendary Archlich, this creature can channel its dark powers to harness the essence of captured souls and unleash it in a devastating manner. The Archlich can use this mythic action once per day:

The Archlich focuses its malevolent will on the souls it has absorbed, drawing upon their combined power. It releases a wave of necrotic energy in a 60-foot cone originating from itself. This wave consumes the souls it has collected, unleashing their combined torment.

• All creatures within the cone must make a DC 23 Constitution saving throw. On a failed save, a creature takes 10d10 necrotic damage and has its hit point maximum reduced by the same amount. On a successful save, the creature takes half damage and isn't affected by the hit point maximum reduction.

• Any creature reduced to 0 hit points by this ability has its soul consumed entirely by the Archlich, preventing any form of resurrection or afterlife for that creature.

• After using Soul Reaver, the Archlich loses all the temporary hit points gained from its Soul Leech special trait and must spend 1d6 days to regain the ability to use Soul Reaver again.