Gargantuan Celestial (Avatar), Chaotic Evil
Armor Class 25 (Natural Armor)
Hit Points 875 (50d20 + 350)
Speed 60 ft., fly 120 ft., swim 60 ft.
Saving Throws
STR +18, DEX +11, CON +17, INT +9, WIS +13, CHA +15
Skills
Intimidation +23, Perception +21, Arcana +16
Damage Resistances
Bludgeoning, Piercing, and Slashing from nonmagical weapons
Damage Immunities
Fire, Cold, Lightning, Acid, Poison, Necrotic; Psychic
Condition Immunities
Charmed, Frightened, Paralyzed, Poisoned, Stunned
Senses
Truesight 120 ft., Passive Perception 31
Languages
All, Telepathy 120 ft.
Challenge
CR 30 (155,000 XP)
Legendary Resistance (5/Day)
If Tiamat fails a saving throw, she can choose to succeed instead.
Divine Body
Tiamat’s form cannot be banished, transported, or imprisoned by mortal means.
Chromatic Majesty
Each of Tiamat’s heads represents a chromatic domain: Red (Fire), Blue (Lightning), Green (Poison), Black (Acid), and White (Cold). She can use one breath weapon per round without repeating the same head until all have been used.
Empowered by Fear
Tiamat has advantage on all attacks against creatures that are frightened. Whenever a creature fails a saving throw against fear while within 60 feet of Tiamat, she regains 30 hit points.
Actions
Turn Structure – Multiheaded Fury
In this combat system, Tiamat acts five times per round—once for each head. She takes a full turn with each, using the abilities tied to that head’s nature.
Each head’s turn can include movement, one breath weapon (if available), and one melee attack. She cannot repeat the same breath weapon until all five have been used (cycling through her chromatic aspects).
Head Order (Repeat after 5 turns):
- Red Head (Fire) – Aggressive melee and fire breath
- Blue Head (Lightning) – Targeted strike and lightning breath
- Green Head (Poison) – Debilitating poison breath and crowd control
- Black Head (Acid) – Armor-breaking acid and terrain manipulation
- White Head (Cold) – Battlefield control and movement restriction
Each head uses:
- Bite (Head-specific) – +18 to hit, 28 (4d10 + 10) damage of that head’s type
- Breath Weapon (if not on cooldown)
- Movement (each head may move the body, but total movement speed per round remains 60 ft. walk, 120 ft. fly)
---### Bite (Head-specific) Melee Weapon Attack: +18 to hit, reach 15 ft., one target. Hit: 28 (4d10 + 10) damage of that head’s type.
Tail Swipe
Melee Weapon Attack: +18 to hit, reach 30 ft., all creatures in a 20 ft. arc. Hit: 35 (6d10 + 8) bludgeoning damage.
Breath Weapons (Recharge 5–6)
Each breath weapon is a 90-ft. cone or 120-ft. line (width 10 ft.). DC 24 Dex or Con save based on the type.
- Red (Fire): 88 (16d10) fire damage
- Blue (Lightning): 77 (14d10) lightning damage
- Green (Poison): 66 (12d10) poison damage + poisoned (1 min)
- Black (Acid): 71 (13d10) acid damage
- White (Cold): 60 (11d10) cold damage + speed halved for 1 round
Legendary Actions (Reset at the end of each full round)
Tiamat can use 3 legendary actions per round, distributed as desired between her 5 turns. Only one legendary action may be used per head’s turn.
Wing Buffet
Each creature within 15 feet must succeed on a DC 24 Strength save or be knocked prone and take 22 (4d8 + 4) bludgeoning damage.
Fear Gaze
Target one creature within 60 feet. It must succeed on a DC 21 Wisdom save or be frightened for 1 minute. Repeat save at the end of each turn.
Chromatic Surge (Costs 2 Actions)
Tiamat activates a random head’s energy in a 20-ft. radius around her. Roll 1d5 to determine element. Each creature in range takes 40 damage of that type (DC 24 Dex or Con save for half).
Wing Buffet
Each creature within 15 feet must succeed on a DC 24 Strength save or be knocked prone and take 22 (4d8 + 4) bludgeoning damage.
Fear Gaze
Target one creature within 60 feet. It must succeed on a DC 21 Wisdom save or be frightened for 1 minute. Repeat save at the end of each turn.
Chromatic Surge (Costs 2 Actions)
Tiamat activates a random head’s energy in a 20-ft. radius around her. Roll 1d5 to determine element. Each creature in range takes 40 damage of that type (DC 24 Dex or Con save for half).
Mythic Trait – Queen of Dragons (One-Time Use)
When reduced to 0 HP, Tiamat roars with divine fury. All heads erupt in a catastrophic explosion of power. All enemies within 120 feet must make a DC 24 Con saving throw or take 100 (20d10) damage of a random chromatic type. Tiamat then rises with 300 HP and loses access to breath weapons but gains Deathflame Aura:
Deathflame Aura (While active)
At the start of each of Tiamat’s turns, all creatures within 30 feet take 30 (6d10) radiant + 30 (6d10) necrotic damage.
This avatar is a reflection of her divinity—a shadow that carries the wrath of a goddess. Slaying it is no small feat, even with the blessings of Silverhand and the will of the free peoples of Faerûn.