Swarm of Death

Gargantuan swarm of Medium undead, chaotic evil

Armor Class 18 (natural armor)
Hit Points 330 (20d20+120)
Speed 40 ft., climb 30 ft., swim 30 ft.

STR	DEX	CON	INT	WIS	CHA
19 (+4)	18 (+4)	23 (+6)	15 (+2)	18 (+4)	14 (+2)

Skills Perception +11, Stealth +18
Damage Resistances acid, fire, lightning, psychic, thunder; bludgeoning, piercing, slashing
Damage Immunities cold, necrotic, poison
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, prone, restrained, stunned
Senses darkvision 120 ft., passive Perception 21
Languages Common, Undercommon
Challenge 22 (41,000 XP)

SPECIAL TRAITS

• Aura of Undeath. At the start of each of the swarm’s turns, each creature within 15 feet of it takes 14 (3d8) necrotic damage. A creature that touches the swarm or hits it with a melee attack while within 15 feet of it takes 10 (3d6) necrotic damage.
• Magic Resistance. The swarm has advantage on saving throws made against spells and other magical effects.
• Swarm. The swarm can occupy another creature’s space and vice versa, and the swarm can move through any opening large enough for a Medium undead. The swarm can’t regain hit points from spells or potions, and it cannot gain temporary hit points.
• Turn Immunity. The swarm is immune to effects that turn undead.

ACTIONS

• Touch of Undeath. Melee Weapon Attack: +11 to hit, reach 0 ft., any number of creatures in the swarm’s space (make a separate attack roll for each). Hit: 17 (2d12+4) slashing damage, or 10 (1d12+4) slashing damage if the swarm has half of its hit points or fewer. In addition, a target is grappled (escape DC 19) and takes 10 (3d6) necrotic damage. A target’s hit point maximum is reduced by an amount equal to the necrotic damage taken, and the swarm regains hit points equal to that amount. The reduction lasts until a target finishes a long rest. A target dies if this effect reduces its hit point maximum to 0.

LEGENDARY ACTIONS

The swarm 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 swarm regains spent legendary actions at the start of its turn.

• Attack. The swarm makes an attack.
• Move. The swarm moves up to half its speed.
• Channel Negative Energy (Costs 2 Actions). The swarm magically unleashes negative energy. Creatures within 60 feet of the swarm, including ones behind barriers and around corners, can’t regain hit points until the end of the swarm’s next turn.

ABOUT

Battlefields littered with festering corpses and unblessed mass graveyards can spawn a horror that brings about more death than most conflicts manage in the first place. These shambling swarms of the undead have no purpose, no desires, and rarely any master other than a fundamental need to snuff out all that which lives.