5e:Deep Dragon/Lair Actions

Deep Dragon's Lair

Deep dragons [lair] in well-hidden caves or sunless beaches in the Underdark … covered in … mold and moss, … larger mushrooms and plants…

The challenge rating of a legendary deep dragon increases by 1 when it's encountered in its lair.

Lair Actions

When fighting inside its lair, an deep dragon can use 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:

• Deep Torpor.
• Mossy Sludge.
• Toxic Spores.

Regional Effects

The region surrounding a legendary deep dragon's lair is altered by the dragon's magic, creating one or more of the following effects:

• Preservation of Knowledge.
• Restless Sleep.
• Verdant Growth.

If the dragon dies, these effects fade over the course of 1d10 days.