Alduin, The World-Eater

World-Eater Wrath (Recharges after a Short or Long Rest). If Alduin would be reduced to 0 hit points, his current hit point total instead resets to 500 hit points, he recharges his Alduin Flare and he regains any expended uses of Legendary Resistance. Additionally, Alduin can now use the options in the "Mythic Actions" section for 1 hour. Award a party an additional 155,000 XP (310,000 XP total) for defeating Alduin after his World-Eater Wrath activates.

Legendary Resistance (5/Day). If Alduin fails a saving throw, his can choose to succeed instead.

Multiattack. Alduin makes one Bite attack, one Claw attack, and one Tail attack.

Bite. Melee Weapon Attack: +19 to hit, reach 20 ft., one target. Hit: 23 (2d12 + 10) piercing damage plus 19 (3d12) force damage.

Claw. Melee Weapon Attack: +19 to hit, reach 15 ft., one target. Hit: 21 (2d10 + 10) slashing damage. If the target is a Huge or smaller creature, it is grappled (escape DC 20) and is restrained until this grapple ends. Alduin can have only one creature grappled this way at a time.

Tail. Melee Weapon Attack: +19 to hit, reach 15 ft., one target. Hit: 23 (2d12 + 10) bludgeoning damage. If the target is a creature, it must succeed on a DC 27 Strength saving throw or be knocked prone.

Akatosh Flames (Recharge 5–6); Alduin exhales multicolored flames in a 300-foot cone. Each creature in that area must make a DC 27 Dexterity saving throw. On a failed save, the creature takes 71 (11d12) damage of a type of Alduin’s choosing: cold or fire. On a successful save, the creature takes half as much damage.

Alduin 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. Alduin regains spent legendary actions at the start of his turn.

Attack. Alduin makes one Claw or Tail attack.

Furious Bite (Costs 2 Actions). Alduin makes one Bite attack. If the attack hits a creature, the target must succeed on a DC 27 Wisdom saving throw or become frightened of Alduin until the end of its next turn.

If Alduin’s World-Eater Wrath trait has activated in the last hour, she can use the options below as legendary actions.

Meteor Storm (Costs 2 Actions). Blazing orbs of fire plummet to the ground at four different points you can see within range. Each creature in a 40-foot-radius sphere centered on each point you choose must make a Dexterity saving throw (DC 25). The sphere spreads around corners. A creature takes 20d6 fire damage and 20d6 bludgeoning damage on a failed save, or half as much damage on a successful one. A creature in the area of more than one fiery burst is affected only once.

Alduin Flare (Costs 3 Actions). Alduin flares with elemental energy. Each creature of the Alduin’s choice in a 60-foot-radius sphere centered on his must make a DC 27 Dexterity saving throw. On a failed save, the creature takes 39 (6d12) damage of a type chosen by Alduin; cold or fire. On a successful save, the creature takes half as much damage.