Ice Walk. The dragon can move across and climb icy surfaces without needing to make an ability check. Additionally, difficult terrain composed of ice or snow doesn't cost it extra movement.
Multiattack. The dragon makes three attacks: one with its bite and two with its claws.
Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 18 (2d10 + 5) piercing damage plus 10 (3d6) cold damage.
Claw. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 5) slashing damage.
Cold Breath (Recharge 5–6). The dragon exhales an icy blast in a 60-foot cone. Each creature in that area must make a DC 18 Constitution saving throw, taking 56 (8d12) cold damage on a failed save, or half as much damage on a successful one.
Frostbolt Barrage (Recharge 5–6). CryoVain unleashes a barrage of freezing projectiles infused with arcane power. CryoVain targets up to three creatures it can see within 120 feet. Each target must make a DC 18 Dexterity saving throw. On a failed save, the target takes 14 (4d6)cold damage as icy bolts strike them unerringly. On a successful save, the target takes half damage.
Glacial Barrier (Recharge 5–6). When CryoVain is targeted by a ranged weapon attack or a spell that requires a ranged attack roll while he is aware of the attacker, he can use his reaction to summon a barrier of ice. The attack or spell must make a DC 18 Dexterity saving throw. On a failed save, the attack or spell is blocked by the barrier, causing it to shatter harmlessly against the ice. CryoVain takes no damage from the attack or spell. On a successful save, CryoVain takes half damage from the attack or spell as the barrier partially forms in time
CryoVain 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. CryoVain regains spent legendary actions at the start of its turn.
- Bite.
- Claw.
- Cold Breath (Costs 2 Actions).
- Glacial Barrier (Costs 2 Actions).
- Frostbolt Barrage (Costs 2 Actions).