Baptist Leviathan

Regeneration: The Baptist Leviathan regains 20 hit points at the start of its turn if it has at least 1 hit point and isn't incapacitated. If the Baptist Leviathan takes radiant, acid, or fire damage, it does not regenerate hit points in that round. If it takes radiant damage, this trait doesn't function for 3 rounds instead of 1.

Legendary Resistance (3/Day): If the Baptist Leviathan fails a saving throw, it can choose to succeed instead.

Growing Wings: The Baptist Leviathan can use its hardening ability to transform its arms into wings, granting it the power of flight and the capability to execute devastating wing attacks.

Multiattack: The Baptist Leviathan can use its greataxe, make one slam attack, and one bite attack.

Greataxe: Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 18 (2d8 + 7) slashing damage.

Slam: Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 18 (2d10 + 7) bludgeoning damage.

Bite: Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 21 (2d12 + 7) piercing damage.

Wing Attack: The Baptist Leviathan turns its arms into wings and makes a wing attack. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 16 (2d8 + 7) slashing damage.

Spiked Armor (Reaction): When grappled, the Baptist Leviathan can use its hardening ability to create spikes on its armor, dealing 14 (2d6 + 7) piercing damage to the grappling creature.

Legendary Actions: The Baptist Leviathan 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 Baptist Leviathan regains spent legendary actions at the start of its turn.

Attack: The Baptist Leviathan makes one slam or bite attack.

Regenerate (Costs 2 Actions): The Baptist Leviathan uses its regeneration trait.

Roar (Costs 3 Actions): Each creature of the Baptist Leviathan's choice within 30 feet of it must succeed on a DC 15 Wisdom saving throw or become frightened for 1 minute. A frightened creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.