gargantuan dragon(fiendish dragon), lawful evil
Armor Class 25 (natural armor)
Hit Points 736 (20d20+400)
Speed 40 ft, swim 40 ft, fly 80 ft
Saving Throws Intelligence (+20) and Dexterity (+20)
Skills Arcana (+20), History (+20), Investigation (+20), Deception (+15), Persuasion (+15), Stealth (+19)
Damage Immunities poison, cold, fire, lightning, acid, non magical wappons, spells below the 6th spell slot
Condition Immunities poisoned, stunned, exhausted, incapacitated, charmed, paralyzed
Senses passive Perception 28, Truesight, Blindsight 120 ft
Languages all, Telepathy 60 ft
Challenge 30 (155,000 XP)
Feature Name. Feature description
Legendary resistance (5/day) if Tiamat fails a saving throw she can choose to succeed instead.
Regeneration Tiamat does regenerate +30 hp every round.
Multi attack. Tiamat can make up to 3 attacks in one round AND breath fire, poison, lightning, acid OR cold, Bite, Claw Attack and Tail Attack. She can use every on these actions once per turn.
Bite. Melee Weapon Attack: +17 to hit, reach 5 ft., one target. Hit: 15 (2d8 + 9) piercing damage.
Claw Attack. Melee Weapon Attack: +17 to hit, reach 5 ft., one target. Hit: 20 (2d12 + 9) slashing damage.
Tail Attack. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 20 (2d8 + 9) slashing damage.
Frost Breath. Tiamat exhales ice in a 120-foot cone. Each of the creatures in that area must make a DC 25 dexterity saving throw or take 80(12d12) cold damage on a failed save and half as much on a successful one.
Breath of fire. Area of effect:One of Tiamats heads exhales fire, every target standing in a 120 ft range in front of Tiamats head, must make a DC 25 Dexterity saving throw, taking 40(12d12) fire damage, on a successful saving throw you take half damage. The heat of the fire can melt buildings made of stone.
Lightning Breath. Tiamat exhales a line of lighting that is 10 feet wide and up to 400 feet long. Each creature in that line must make a DC 25 dexterity saving throw or take 70(12d12) lighting damage on a failed save and half as much on a successful one.
poisonous Breath. Tiamat exhales poison in an area of 120 ft in front of her. Each creature in that area must make a DC 25 dexterity saving throw, taking 87(12d12) poison damage and become poisoned for 2d8 days on a failed save and half as much on a successful one.
Acid Breath. Tiamat exhales acid in a 200-foot line that is 10 feet wide. Each creature in that line must make a DC 25 dexterity saving throw or take 60(12d12) acid damage on a failed save and half as much on a successful one.
Interrupting scream (refresh on a 5 on a d6.) Area of effect: One of Tiamat's heads screams in a direction and sends a pressure wave out. Every Target standing in a 90 ft range ahead of Tiamat must succeed a DC 20 constitution saving throw or will be exhausted for the next minute. If you are channelling a spell while this, you will have disadvantage on the saving throw and if you get hit, you will be stunned for 2 turns.
The 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 regains spent legendary actions at the start of its turn.
Death zone(channeling for up to 1 minute)(refreshes on a roll of a 6 on a d6). Area of effect: All 5 heads of Tiamat exhale their fire, lightning, acid, cold, poison breath at the same time and create a 60 ft radius death zone. If you try to pass the death zone, you have to make a DC 30 Dexterity saving throw or you will get 30(3d20) from every damage source.(3d20 * 5)
If you already are in the death zone you have to make a DC 25 Dexterity saving throw or take 75(1d20) damage from every source listed at the top in the first round and he whole damage in every following round. If you are immune to you a damage source you will take a fifth less damage per source, if you are immune to all sources you will just have the effect of interrupting scream.
Wing Attack (costs 2 actions). Tiamat beats her wings. Each creature within 80 feet of him must succeed a DC 25 dexterity saving throw or take 80(10d12) bludgeoning damage and be knckoed prone.