Gargantuan dragon (fiend), chaotic evil

Armor Class: 22

Hit Points: 22d20+242

Speed: 40 ft , fly: 120 ft , climb: 40 ft

STR

30 +10

DEX

12 +1

CON

25 +7

INT

22 +6

WIS

15 +2

CHA

25 +7

Saving Throws: STR +18, DEX +9, CON +17, WIS +12, CHA +15

Skills: Perception +16, Stealth +7

Damage Vulnerabilities: Radiant

Damage Resistances: Cold, Lightning; Bludgeoning, Piercing, and Slashing from Non-magical Attacks

Damage Immunities: Fire, Poison

Condition Immunities: Charmed, Poisoned

Senses: Blindsight 60 ft., Darkvision 120 ft., Truesight 40 ft., Passive Perception 26

Languages: Abyssal, Common, Draconic, Infernal

Challenge Rating: 25

Proficiency Bonus: +8

Actions

Multiattack. The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws or the dragon then makes three attacks: one with its bite, one with its claw and one with its tail.   Bite. Melee Weapon Attack: +20 to hit, reach 15 ft., one target. Hit: 23 (2d10 + 12) piercing damage plus 14 (4d6) fire damage.   Claw. Melee Weapon Attack: +20 to hit, reach 10 ft., one target. Hit: 19 (2d6 + 12) slashing damage.   Tail. Melee Weapon Attack: +20 to hit, reach 20 ft., one target. Hit: 21 (2d8 + 12) bludgeoning damage.   Frightful Presence. Each creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 21 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next 24 hours.   Fire Breath (Recharge 5–6). The dragon exhales fire in a 90-foot cone. Each creature in that area must make a DC 25 Dexterity saving throw, taking 91 (26d6) fire damage on a failed save, or half as much damage on a successful one.   Demon's Essense Fire Breath (Recharge 5-6). The dragon exhales smoke with crackling crackling embers that explode with fire on contact in a 40-foot cone. Each creature in that area must make a DC 23 Dexterity saving throw, taking 76 (15d8) fire damage on a failed save, or half as much damage on a successful one.   Demonic Dragon's Cry (Only usable after the dragon makes two breath attacks) (Recharge 6). The dragon yells a mighty roar and then lower his mouth as he exhales fire and black smoke with crackling embers inside the smoke in a 90-foot cone, and tears a hole in the planar barier to summon reinforcements or flee. Each creature in that area must make a DC 21 Dexterity save with disadvantage, taking (27d10+6) on a failed save, or no damage on a successful one. After use the dragon's breath attacks aside from this one are no longer recharge for the day.   Teleport. The dragon magically teleports, along with any equipment or creature it is wearing or carrying, up to 120 feet to an unoccupied space it can see.

Legendary Actions

The dragon 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 dragon regains spent legendary actions at the start of its turn.   Detect. The dragon makes a Wisdom (Perception) check.   Tail Attack. The dragon makes a tail attack.   Teleport (Costs 2 Actions). The dragon uses it's teleport.   Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 15 feet of the dragon must succeed on a DC 25 Dexterity saving throw or take 17 (2d6 + 10) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.