Legendary Resistance (5/Day). If the void guardian fails a saving throw, it can choose to succeed instead.
Maddening Aura. At the start of each of the void guardian's turns, each creature within 120 feet of it takes (1d100) 1d100 percent damage.
Multiattack. The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its tail.
Frightful Presence. Each creature of the void guardian's choice that is within 240 feet of the guardian and aware of it must succeed on a DC 20 Wisdom saving throw or become frightened for 2 turns. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the to the void guardian's Frightful Presence for the next 24 hours.
Bite. Melee Weapon Attack: +16 to hit, reach 120 ft., one target. Hit: 100 (10d10+9) 10d10+9 piercing damage.
Tail. Melee Weapon Attack:
+16 to hit, reach 240 ft., one target. Hit: 180 (18d10+9) 18d10+9 bludgeoning damage.