Actions

Multiattack. The dragon uses its frightful presence and then makes three attackes: one with its bite and two with its claws.   Bite. Melee Weapon Attack: +17 to hit, reach 3 sq., one target. Hit: 20 ( 2d10+9 ) percing damage and 14 ( 4d6 ) fire damage.   Claw. Melee Weapon Attack: +17 to hit, reach 2 sq., one target. Hit: 16 ( 2d6+9 ) slashing damage.   Tail. Melee Weapon Attack +17 to hit, reach 4 sq., one target. Hit: 18 ( 2d8+9 ) bludgeoning damage.   Frightful Presence. Each creature of the dragon's choice that is within 24 squares of the dragon must succeed in a DC 24 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 effoct on itself on a success. If a creature's saving throw is successful or the effect ends, the creature is immune to the dragons frightful presence for the next 24 hours.   Hellfire Breath (Recharge 1d6>=5 ). The dragon exhales hellfire in a 12 sq. cone. Each creature in that area must make a DC 25 dexterity saving throw, taking 77 ( 22d6 ) hellfire damage on a failed save, or half as much on a successful one.   Infernal Summons. Once per day, the hellfire wyrm can summon a horned devil from the Nine Hells. It remains for one hour, at which point it returns back to werever it was summoned from.   Change Shape. A hellfire wyrm can assume the form a medium, large or huge tiefling or devil, or revert back to its original form. They revert back to their original form when they die. Any equipment worn or carried by the wyrm is either absorbed or borne by the new form (dragons choice).   In a new form, the dragon retains its alignment, hit points, hit dice, ability to speak, proficiencies, legendary resistance, lair actions, and intelligence, wisdom and charisma scores, as well as this action. Their statistics and capabilities are otherwise replaced by those of the new form, except any class features or legendary actions of that form.

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 Wisdon (Perception) check.   Tail Attack. The dragon makes a tail attack.   Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 3 squares of the dragon must succeed a DC 25 dexterity saving throw or take 17 ( 2d6+10 ) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.

Lair Actions

On initiative count 20 (losing initiative ties), the dragon takes a lair action to cause one of the following effects; the dragon can't use the same effect two rounds in a row:  

• Hellfire magma erupts from a point on the ground the dragon can see within 24 squares of them, creating a 4 square high, 1 square radius geyser. Each creature in the geyser's area must make a DC 15 dexterity throw, taking 21 ( 6d6 ) hellfire damage on a failed save, or half as much damage on a successful one.
• A tremor shakes the lair in a 12 square radius around the dragon. Each creature other than the dragon on the ground in that area must succeed on a DC 15 dexterity throw or be knocked prone.
• Infernal gases form a cloud in a 4 square radius sphere centered around a point the dragon can see within 24 squares of them. The sphere spreads around corners, and its area is lightly obscured. It lasts until the next lair action is taken. Each creature that starts its turn in the cloud must succeed on a DC 13 Constitution saving throw or be poisoned until the end of its turn. While poisoned in this way, a creature is incapacitated.

Hellfire lairs anywhere they please on the rare occasions that they do. These lairs become highly corrupted with infernal energies that cause the environment to change significantly.

Regional Effects

The region containing an ancient hellfire dragons lair is warped by the dragon's magic, which creates one or more of the following effects:  

• Small earthquakes are common within 10km of the dragons lair.
• Water sources within 2 km of the lair are warm and tainted by sulfur.
• Fissures within 2 km of the lair form portals to the Nine Hells of Baator, allwoing creatures of the hells inot the world to dwell nearby.

Suggested Environments

Nine Hells of Baator