Great Aquamentus (5e Creature)
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Huge dragon, neutral evil
Saving Throws Str +11, Con +9, Int +6, Wis +8
Charge. If the aquamentus moves at least 20 feet straight toward a target and then hits it with a gore attack on the same turn, the target takes an extra 13 (2d12) piercing damage. If the target is a creature, it must succeed on a DC 20 Strength saving throw or be pushed up to 10 feet away and knocked prone.
Innate Spellcasting. The aquamentus' innate spellcasting ability is Charisma (spell save DC 19, +11 to hit with spell attacks). The aquamentus can innately cast the following spells, requiring no material components:
Legendary Resistance (3/Day). If the aquamentus fails a saving throw, it can choose to succeed instead.
Magic Resistance. The aquamentus has advantage on saving throws against spells and other magical effects.
Weak Point. An attack which specifically targets the aquamentus' horn bypasses its damage immunity, but the aquamentus still takes nonmagical bludgeoning, piercing, and slashing damage as though it resisted it, and full magical bludgeoning, piercing, and slashing damage. Any attack roll made as a called shot, such as against this weak point, is normally made with disadvantage.
Multiattack. The aquamentus casts a spell, makes a claw attack, and makes a gore attack.
Claw. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 19 (4d6 + 5) slashing damage.
Gore. Melee Spell Attack: +11 to hit, reach 10 ft., one target. Hit: 31 (4d12 + 5) piercing damage.
The aquamentus 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 aquamentus regains spent legendary actions at the start of its turn.
Claw Attack. The aquamentus makes a claw attack.
Detect. The aquamentus makes a Wisdom (Perception) check. It can cast detect weapons, locate object, or see invisibility as part of this legendary action if it would otherwise be able to cast the spell.
Fly Back. The aquamentus uses the Disengage action and flies up to 20 feet.
Scorching Ray. The aquamentus casts scorching ray.
Gigantic green-colored dragons, any aquamentus is a rare but terrifying monster. Warriors can rarely even do it harm unless they strike the creature's singular horn, the source of the dragon's magical prowess. Such a task would be difficult on its own, let alone with the monster blasting out magical flames at any would-be foes.
A great aquamentus, unlike its more common counterpart, has over many decades attained not only respectable intelligence and greater strength and size, but honed mastery over its magical abilities. Few foes can stand before its flames without being reduced to ash.
A great aquamentus retains an inherent interest in magic and magic items, and has developed even greater means of locating identifying such items. Its treasure hoard is no doubt packed with numerous magical trinkets.
- Aquamentus, the more common form of this creature