Long ago the ancient white dragon Volidrake mastered a prehistoric form of storm magic. He now rules over a tribe of half-white dragon berserkers who worship him as a primordial god of storms and war.

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:

• Freezing fog fills a 20-foot-radius sphere centered on a point the dragon can see within 120 feet of it. The fog spreads around corners, and its area is heavily obscured. Each creature in the fog when it appears must make a DC 10 Constitution saving throw, taking 10 (3d6) cold damage on a failed save, or half as much damage on a successful one. A creature that ends its turn in the fog takes 10 (3d6) cold damage. A wind of at least 20 miles per hour disperses the fog. The fog otherwise lasts until the dragon uses this lair action again or until the dragon dies.
• Jagged ice shards fall from the ceiling, striking up to three creatures underneath that the dragon can see within 120 feet of it. The dragon makes one ranged attack roll (+7 to hit) against each target. On a hit, the target takes 10 (3d6) piercing damage.
• The dragon creates an opaque wall of ice on a solid surface it can see within 120 feet of it. The wall can be up to 30 feet long, 30 feet high, and 1 foot thick. When the wall appears, each creature within its area is pushed 5 feet out of the wall’s space, appearing on whichever side of the wall it wants. Each 10-foot section of the wall has AC 5, 30 hit points, vulnerability to fire damage, and immunity to acid, cold, necrotic, poison, and psychic damage. The wall disappears when the dragon uses this lair action again or when the dragon dies.
• Lightning arcs, forming a 5-foot-wide line between two of the lair’s solid surfaces that the dragon can see. They must be within 120 feet of the dragon and 120 feet of each other. Each creature in that line must succeed on a DC 15 Dexterity saving throw or take 10 (3d6) lightning damage.

Regional Effects

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

• Chilly fog lightly obscures the land within 6 miles of the dragon’s lair.
• Once per day, the dragon can alter the weather in a 6-mile radius centered on its lair. The dragon doesn’t need to be outdoors; otherwise the effect is identical to the control weather spell.
• Freezing precipitation falls within 6 miles of the dragon’s lair, sometimes forming blizzard conditions when the dragon is at rest.
• Icy walls block off areas in the dragon’s lair. Each wall is 6 inches thick, and a 10-foot section has AC 5, 15 hit points, vulnerability to fire damage, and immunity to acid, cold, necrotic, poison, and psychic damage.
  If the dragon wishes to move through a wall, it can do so without slowing down. The portion of the wall the dragon moves through is destroyed, however.
• Humanoids, Beasts, and Monstrosities that are born within 6 miles of the lair have a high likelihood of being half-dragons.

If the dragon dies, changed weather reverts to normal, as described in the spell, the fog and precipitation fade within 1 day. The ice walls melt over the course of 1d10 days.