Red Dragon

Lair Actions

Source: Monster Manual

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:

• Magma erupts from a point on the ground the dragon can see within 120 feet of it, creating a 20-foot-high, 5-foot-radius geyser. Each creature in the geyser’s area must make a DC 15 Dexterity saving throw, taking dice:6d6|noform|noparens|avg|text(21) (6d6) fire damage on a failed save, or half as much damage on a successful one.
• A tremor shakes the lair in a 60-foot radius around the dragon. Each creature other than the dragon on the ground in that area must succeed on a DC 15 Dexterity saving throw or be knocked prone.
• Volcanic gases form a cloud in a 20-foot-radius sphere centered on a point the dragon can see within 120 feet of it. The sphere spreads around corners, and its area is lightly obscured. It lasts until initiative count 20 on the next round. 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.

Additional Lair Actions

At your discretion, a legendary (adult or ancient) red dragon can use one or both of the following additional lair actions while in its lair:

• Noxious Smoke. A cloud of thick, dark smoke fills a 20-foot-radius sphere centered on a point the dragon can see within 120 feet of it. The sphere spreads around corners, and its area is heavily obscured. A creature other than the dragon that starts its turn in the cloud or enters it for the first time on its turn must succeed on a DC 15 Constitution saving throw or be poisoned until the end of its turn. The cloud lasts until initiative count 20 on the next round.
• Searing Heat. Searing heat spreads out in a 15-foot-radius sphere centered on a point the dragon can see within 120 feet of it. Any creature that enters the affected area or starts its turn there must make a DC 15 Constitution saving throw, taking dice:3d6|noform|noparens|avg|text(10) (3d6) fire damage on a failed save, or half as much damage on a successful one. The heat lasts until initiative count 20 on the next round.

Regional Effects

Source: Monster Manual

The region containing a legendary red dragon’s lair is warped by the dragon’s magic, which creates one or more of the following effects:

• Small earthquakes are common within 6 miles of the dragon’s lair.
• Water sources within 1 mile of the lair are supernaturally warm and tainted by sulfur.
• Rocky fissures within 1 mile of the dragon’s lair form portals to the Elemental Plane of Fire, allowing creatures of elemental fire into the world to dwell nearby.

If the dragon dies, these effects fade over the course of dice:1d10|noform|noparens|avg (1d10) days.

Additional Regional Effects

Any of these effects might appear in the area around a red dragon’s lair, in addition to or instead of the effects described in the Monster Manual:

• Desertification. Precipitation is almost nonexistent within 6 miles of the dragon’s lair, making the land parched and arid and most plant life withered and brown.
• Fiery Senses. The dragon can hear up to 30 feet through any open flame within 1 mile of the dragon’s lair.
• Ominous Flames. Open flames within 6 miles of the dragon’s lair are tinged dark red, hiss and crackle constantly, and throw off embers and showers of sparks.