Huge Dragon, neutral
Armor Class 19 (natural armor)
Hit Points 297 (22d12+154)
Speed fly +80, swim +40, walk +40
Challenge 20
Saving Throws cha +10, con +13, dex +7, wis +9
Skills arcana +10, history +10, insight +9, stealth +7, perception +15
Damage Immunities lightning, thunder
Senses blindsight 60 ft., darkvision 120 ft., passive Perception 25
Languages all
Amphibious. The dragon can breathe air and water.
Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.
Truespeak. The dragon can communicate with any living creature as if they shared a language.
Innate Spellcasting. The imperial dragon's innate spellcasting ability is Charisma (spell save DC 18). It can innately cast the following spells, requiring no material components. At will: fog cloud 3/day each: control water, gust of wind, stinking cloud 1/day each: cloudkill, control weather
Multiattack. The dragon can use its Mesmerizing Presence. It then makes three attacks: one with its bite and two with its claws.
Bite. Melee Weapon Attack: +14 to hit, reach 10 ft., Hit: 19 (2d10 + 8) piercing damage.
Claw. Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 15 (2d6 + 8) slashing damage.
Tail. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 17 (2d8 + 8) bludgeoning damage.
Mesmerizing 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 20 Wisdom saving throw or become charmed by the dragon 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 Mesmerizing Presence for the next 24 hours.
Lightning Breath (Recharge 5-6). The dragon exhales lightning in a 90-foot line that is 5 feet wide. Each creature in that line must make a DC 21 Dexterity saving throw, taking 55 (10d10) lightning damage on a failed save, or half as much damage on a successful one.
Change Shape. The dragon magically polymorphs into a humanoid or beast that has a challenge rating no higher than its own, or back into its true form. It reverts to its true form if it dies. Any equipment it is wearing or carrying is absorbed or borne by the new form (the dragon's choice). In a new form, the dragon retains its alignment, hp, Hit Dice, ability to speak, proficiencies, Legendary Resistance, lair actions, and Intelligence, Wisdom, and Charisma scores, as well as this action. Its statistics and capabilities are otherwise replaced by those of the new form, except any class features or legendary actions of that form. The dragon can choose to transform only part of its body with this action, allowing it to sprout rabbit-like ears or a humanoid head. These changes are purely cosmetic and don't alter statistics.
The dragon can take 3 legendary actions, choosing from the options below. Only one legendary action 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.
Cast a Spell (Costs 3 Actions). The dragon casts a spell from its list of innate spells, consuming a use of the spell as normal.
Source: Tome of Beasts 2 · OGL/Open