Styx Dragon. Also known as shadowdrakes or darkwyrms, Styx dragons haunt the putrid waters of the River Styx throughout its nearly infinite length. One of the few creatures immune to the harmful effects of the river, Styx dragons swim with impunity across the top layers of all the Lower Planes, feasting on fiends and any other creature they can find and catch. A Styx dragon has a long, serpentine body with tiny, flipperlike claws that are useless on land and in combat. Its wings are too small to carry it aloft, but help to propel it through the water.
Its tail splits into two long, bladed whips that it can use to slash and grab its prey. A Styx dragon’s scales are slimy and range from dark brown to rusty red in color. Its eyes glow with a lurid yellow light. Styx dragons make their lairs by burrowing into the mud on the banks of the Styx. They do not like to leave their native plane, but if one is forcibly brought to the Material Plane, it will thrive in fetid water. Styx dragons normally subsist on the flesh of fiends, but enjoy eating any meat— particularly rotting carrion.
Ancient Styx Dragon
Gargantuan dragon, neutral evil
- Armor Class 22 (natural armor)
- Hit Points 388 (21d20 + 168)
- Speed 60 ft., burrow 20 ft., swim 60 ft.
STR DEX CON INT WIS CHA 27 (+8) 10 (+0) 27 (+8) 18 (+4) 17 (+3) 21 (+5)
- Saving Throws Dex +7, Con +15, Wis +10, Cha +12
- Skills Deception +12, Perception +10, Stealth +7
- Damage Immunities acid, poison
- Condition Immunities poisoned
- Senses blindsight 60 ft., darkvision 120 ft., passive perception 20
- Languages Common, Draconic
- Challenge 23 (32,500 XP)
Amphibious. The dragon can breathe air and water.
Magic Weapons. The dragon's attacks are magical.
Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.
Actions
Multiattack. The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its tail.
Bite. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 19 (2d10 + 8) piercing damage plus 10 (3d6) acid damage.
Tail. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 26 (4d8 + 8) slashing damage.
Constrict. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 26 (4d8 + 8) bludgeoning damage, and the target is grappled (escape DC 18). Until this grapple ends, the creature is restrained, and the dragon can't constrict another target or make tail attacks.
Frightful 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 21 Wisdom saving throw or become frightened 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 Frightful Presence for the next 24 hours.
Breath Weapons (Recharge 5-6). The dragon uses one of the following breath weapons.
Acid Breath. The dragon exhales a spurt of acid that sticks to creatures in a 90-foot line that is 5 feet wide. Each creature in that line must make a DC 23 Dexterity saving throw, taking 63 (18d6) acid damage on a failed save, or half as much damage on a successful one. Additionally, if a creature fails its save and takes damage, it also take an extra 29 (8d6) acid damage on the start of its next turn.
Styx Breath. The dragon exhales stupefying gas in a 90-foot cone. Each creature in that area must succeed on a DC 23 Constitution saving throw or have its Intelligence score reduced by 4. If a creature's Intelligence is reduced to 0, the creature is stunned until it regains at least one point of Intelligence.
Legendary Actions
The dragon 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 dragon regains spent legendary actions at the start of its turn.
Detect. The dragon makes a Wisdom (Perception) check.
Bite Attack. The dragon makes a bite attack.
Constrict Attack (Costs 2 Actions). The dragon makes a constrict attack.
Adult Dragon on page below
Adult Styx Dragon
Huge dragon, neutral evil
- Armor Class 19 (natural armor)
- Hit Points 183 (18d12 + 66)
- Speed 60ft., burrow 20ft., swim 60ft.
STR DEX CON INT WIS CHA 24 (+7) 10 (+0) 23 (+6) 16 (+3) 15 (+2) 18 (+4)
- Saving Throws Dex +6, Con +12, Wis +8, Cha +10
- Skills Deception +10, Perception +8, Stealth +6
- Damage Immunities acid, poison
- Condition Immunities poisoned
- Senses blindsight 60 ft., darkvision 120 ft., passive perception 18
- Languages Common, Draconic
- Challenge 16 (15,000 XP)
Amphibious. The dragon can breathe air and water.
Magic Weapons. The dragon's attacks are magical.
Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.
Actions
Multiattack. The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its tail.
Bite. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 18 (2d10 + 7) piercing damage plus 7 (2d6) acid damage.
Tail. Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 21 (3d8 + 7) slashing damage.
Constrict. Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 21 (3d8 + 7) bludgeoning damage, and the target is grappled (escape DC 17). Until this grapple ends, the creature is restrained, and the dragon can't constrict another target or make tail attacks.
Frightful 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 18 Wisdom saving throw or become frightened 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 Frightful Presence for the next 24 hours.
Breath Weapons (Recharge 5-6). The dragon uses one of the following breath weapons.
Acid Breath. The dragon exhales a spurt of acid that sticks to creatures in a 60-foot line that is 5 feet wide. Each creature in that line must make a DC 19 Dexterity saving throw, taking 49 (14d6) acid damage on a failed save, or half as much damage on a successful one. Additionally, if a creature fails its save and takes damage, it also take an extra 22 (6d6) acid damage on the start of its next turn.
Styx Breath. The dragon exhales stupefying gas in a 60-foot cone. Each creature in that area must succeed on a DC 19 Constitution saving throw or have its Intelligence score reduced by 3. If a creature's Intelligence is reduced to 0, the creature is stunned until it regains at least one point of Intelligence.
Legendary Actions
The dragon 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 dragon regains spent legendary actions at the start of its turn.
Detect. The dragon makes a Wisdom (Perception) check.
Bite Attack. The dragon makes a bite attack.
Constrict Attack (Costs 2 Actions). The dragon makes a constrict attack.
Young Dragon on page below
Young Styx Dragon
Large dragon, neutral evil
- Armor Class 18 (natural armor)
- Hit Points 114 (14d10 + 37)
- Speed 60ft., burrow 20ft., swim 60ft.
STR DEX CON INT WIS CHA 20 (+5) 10 (+0) 19 (+4) 14 (+2) 13 (+1) 16 (+3)
- Saving Throws Dex +4, Con +8, Wis +5, Cha +7
- Skills Deception +7, Perception +5, Stealth +14
- Damage Immunities acid, poison
- Condition Immunities poisoned
- Senses blindsight 30 ft., darkvision 120 ft., passive perception 15
- Languages Common, Draconic
- Challenge 9 (5,000 XP)
Amphibious. The dragon can breathe air and water.
Magic Weapons. The dragon's attacks are magical.
Actions
Multiattack. The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its tail.
Bite. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 16 (2d10 + 5) piercing damage plus 7 (2d6) acid damage.
Tail. Melee Weapon Attack: +9 to hit, reach 15 ft., one target. Hit: 19 (3d8 + 5) slashing damage.
Constrict. Melee Weapon Attack: +9 to hit, reach 15 ft., one target. Hit: 14 (3d8 + 5) bludgeoning damage, and the target is grappled (escape DC 15). Until this grapple ends, the creature is restrained, and the dragon can't constrict another target or make tail attacks.
Frightful 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 15 Wisdom saving throw or become frightened 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 Frightful Presence for the next 24 hours.
Breath Weapons (Recharge 5-6). The dragon uses one of the following breath weapons.
Acid Breath. The dragon exhales a spurt of acid that sticks to creatures in a 40-foot line that is 5 feet wide. Each creature in that line must make a DC 15 Dexterity saving throw, taking 42 (12d6) acid damage on a failed save, or half as much damage on a successful one. Additionally, if a creature fails its save and takes damage, it also take an extra 18 (5d6) acid damage on the start of its next turn.
Styx Breath. The dragon exhales stupefying gas in a 30-foot cone. Each creature in that area must succeed on a DC 15 Constitution saving throw or have its Intelligence score reduced by 2. If a creature's Intelligence is reduced to 0, the creature is stunned until it regains at least one point of Intelligence.
Wyrmling Dragon on page below
Styx Dragon Wyrmling
Medium dragon, neutral evil
- Armor Class 17 (natural armor)
- Hit Points 45 (7d8 + 13)
- Speed 50ft., burrow 10ft., swim 50ft.
STR DEX CON INT WIS CHA 16 (+3) 10 (+0) 15 (+2) 12 (+1) 11 (+0) 13 (+1)
- Saving Throws Dex +2, Con +4, Wis +2, Cha +3
- Skills Deception +3, Perception +2, Stealth +2
- Damage Immunities acid, poison
- Condition Immunities poisoned
- Senses blindsight 10 ft., darkvision 60 ft., passive perception 12
- Languages Draconic
- Challenge 3 (700 XP)
Amphibious. The dragon can breathe air and water.
Actions
Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 9 (1d10 + 3) piercing damage plus 3 (1d6) acid damage.
Tail. Melee Weapon Attack: +5 to hit, reach 15 ft., one target. Hit: 12 (2d8 + 3) slashing damage.
Breath Weapons (Recharge 5-6). The dragon uses one of the following breath weapons.
Acid Breath. The dragon exhales a spurt of acid that sticks to creatures in a 15-foot line that is 5 feet wide. Each creature in that line must make a DC 12 Dexterity saving throw, taking 18 (5d6) acid damage on a failed save, or half as much damage on a successful one. Additionally, if a creature fails its save and takes damage, it also take an extra 7 (2d6) acid damage on the start of its next turn.
Styx Breath. The dragon exhales stupefying gas in a 15-foot cone. Each creature in that area must succeed on a DC 12 Constitution saving throw or have its Intelligence score reduced by 1. If a creature's Intelligence is reduced to 0, the creature is stunned until it regains at least one point of Intelligence.