Lord Soth of Sithicus

Medium Undead, Lawful Evil

AC: 18

Initiative: +6 (16)

HP: 228 (24d8 + 120)

Speed: 30 ft.

STR: 22 (+6)
DEX: 11 (+0)
CON: 20 (+5)
INT: 12 (+1)
WIS: 16 (+3)
CHA: 20 (+5)

Saving Throws: Dex +6, Wis +9, Cha +11

Immunities: necrotic; poison

Condition Immunities: exhaustion; frightened; poisoned

Senses: Darkvision 120 ft., Passive Perception 13

Languages: Common, Infernal

CR: 19 (XP 22,000, or 25,000 in lair; PB +6)

Darklord Restoration.

If Lord Soth dies, he revives with all his Hit Points in 1d10 weeks somewhere in Sithicus.

Legendary Resistance (3/Day, or 4/Day in Domain).

If Lord Soth fails a saving throw, he can choose to succeed instead.

Magic Resistance.

Lord Soth has Advantage on saving throws against spells and other magical effects.

Marshal Undead.

Undead creatures of Lord Soth's choice (excluding himself) in a 60-foot Emanation originating from him have Advantage on attack rolls and saving throws. Lord Soth can't use this trait if he has the Incapacitated condition.

Commanding Magic (3/Day).

Lord Soth casts Dispel Magic, Hold Person, or Banishment (level 5 version), using Charisma as the spellcasting ability (spell save DC 19).

3/day: Dispel Magic, Hold Person, Banishment (level 5 version)

Actions

Multiattack.

Lord Soth makes three Forsaken Brand attacks.

Forsaken Brand.

Melee Attack Roll: +12, reach 5 ft. Hit: 10 (1d8 + 6) Slashing damage plus 13 (3d8) Necrotic damage.

Cataclysmic Fire (Recharge 5-6).

Dexterity Saving Throw: DC 19, each creature in a 20-foot-radius Sphere centered on a point Lord Soth can see within 120 feet. Failure: 24 (7d6) Fire damage plus 24 (7d6) Necrotic damage. Success: Half damage.

Face of Death (1/Day).

Charisma Saving Throw: DC 19, each creature in a 60-foot Emanation originating from Lord Soth. Failure: 22 (4d10) Psychic damage, and the creature has the Frightened condition. Success: Half damage only. Failure or Success: If this damage reduces the target to 0 Hit Points, the target dies.

Legendary Actions

Legendary Action Uses: 3. Immediately after another creature’s turn, this creature can expend a use to take one of the following actions; it regains all expended uses at the start of each of its turns.

Punish.

Lord Soth moves up to half his Speed, and he makes one Forsaken Brand attack.

Soth's Command.

Lord Soth casts Command (level 3 version), using the same spellcasting ability as Commanding Magic. Lord Soth can't take this action again until the start of his next turn.

Regional Effects

Sithicus is altered by Lord Soth's presence, creating the following effects:

Closing the Borders. While in his domain, Lord Soth can close or open the borders to Sithicus. While the borders are closed, purple flames fill the Mists surrounding Sithicus. A creature that enters the Mists for the first time on a turn or starts its turn there takes 5 (1d10) Fire damage plus 5 (1d10) Necrotic damage.
Fearless Soldiers. Undead allies of Lord Soth have Immunity to the Frightened condition.
Guilt of Sithicus. Few sleep soundly in Sithicus. Whenever a creature other than Lord Soth and his allies finishes a Long Rest in the domain, the creature must succeed on a DC 10 Constitution saving throw or gain 1 Exhaustion level.

If Lord Soth dies, these effects end immediately.

Find this creature in the encounter builder

Source: Ravenloft: The Horrors Within, p. 158 - Licenses and attribution