Large fiend (devil), lawful evil
Armor Class: 17 (natural armor)
Hit Points: 142 (15d10 + 60)
Speed: 40 ft., swim 60 ft.
STR DEX CON INT WIS CHA
22 (+6) 18 (+4) 18 (+4) 16 (+3) 14 (+2) 20 (+5)
Saving Throws: Str +9, Dex +7, Con +7, Wis +5, Cha +8
Damage Resistances: Cold, Fire, Lightning
Damage Immunities: Poison
Condition Immunities: Poisoned
Senses: Darkvision 120 ft., Passive Perception 12
Languages: Infernal, Aquan, telepathy 120 ft.
Challenge: 10 (5,900 XP)
Traits
· Aquatic Adaptation. The Aquatic Devil can breathe underwater and move through water without impediment. It also has advantage on Strength (Athletics) checks made to swim.
· Fiery Resilience. The Aquatic Devil is resistant to fire damage, as it has adapted to the extreme heat of underwater volcanic environments.
· Infernal Aura. Creatures within 10 feet of the Aquatic Devil take 5 (1d10) fire damage at the start of their turn. This damage ignores resistance to fire.
· Volcanic Presence. The Aquatic Devil can create an intense heat in its surroundings. As a bonus action, it can cause the temperature of the water within a 30-foot radius of it to become scalding hot, dealing 7 (2d6) fire damage to any creature that begins its turn within that area. The Aquatic Devil is immune to this effect. The effect lasts for 1 minute, but the Devil can deactivate it as a bonus action.
Actions
Multiattack. The Aquatic Devil makes two Claw attacks and one Infernal Flame attack.
Claw. Melee Weapon Attack: +9 to hit, reach 10 ft., one target.
Hit: 18 (2d8 + 6) slashing damage plus 7 (2d6) fire damage.
Infernal Flame (Recharge 5-6). The Aquatic Devil unleashes a blast of hellfire in a 30-foot cone. Each creature in the area must make a DC 15 Dexterity saving throw, taking 36 (8d8) fire damage on a failed save, or half as much on a successful one.
Hellish Grasp (Recharge 5-6). The Aquatic Devil targets one creature within 15 feet. The creature must make a DC 17 Strength saving throw or be restrained by the Devil’s fiery grip. While restrained, the creature takes 14 (4d6) fire damage at the start of each of its turns. The creature can use its action to make a Strength check against the DC to break free.
Legendary Actions
The Aquatic Devil can take 1 legendary action, 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 Aquatic Devil regains spent legendary actions at the start of its turn.
Fiery Lash. The Aquatic Devil makes one Claw attack.
Scalding Wave (Costs 2 Actions). The Aquatic Devil causes a wave of heated water to surge forward in a 20-foot line. Each creature in the line must make a DC 15 Dexterity saving throw, taking 21 (6d6) fire damage on a failed save, or half as much on a successful one.
Description
The Aquatic Devil is a terrifying fiend that thrives in the volcanic depths of oceans, particularly in regions where underwater lava flows meet the abyssal depths. These devils are feared by sailors and underwater civilizations alike, as they possess a terrifying mastery over both water and fire. Their molten skin gleams with the heat of the deep, and their horns, sharp as obsidian, are often found glowing with infernal energy.
Aquatic Devils are often summoned by dark cults to oversee undersea cities of sin or serve as enforcers of infernal pacts in the deep. They are brutal in combat, using their fiery claws and hellish powers to overwhelm enemies. Though they are resistant to fire, they are particularly vulnerable to cold—an extreme opposite to their boiling habitat.
In their natural habitat, they reside near underwater volcanoes or the cracks in the ocean floor, where the pressure, heat, and elemental forces mirror the conditions of their hellish homeland. They thrive in this volatile environment, manipulating both fire and water to their advantage, often ambushing intruders with sudden blasts of scalding steam and explosive infernal flames.
Their ultimate goal is to spread the will of the Nine Hells, particularly by instilling fear and suffering among the weak and helpless.