Chaodragon

Siege Monster. The kaiju deals double damage to objects and structures.

Magic Resistance. The kaiju has advantage on saving throws against spells and other magical effects.

Legendary Resistance (3/Day). If the kaiju fails a saving throw, it can choose to succeed instead

Death Throes. When killed, the kaiju explodes in a burst of energy that deals 90 (20d8) fire damage, or half as much on a successful DC 21 Dexterity save, to everything within 100 feet.

Multiattack. The kaiju can use its frightful presence. It then makes five attacks: one with its bite, one with its horns, two with its claws and one with its tail. When its fire breath is available, it can use the breath in place of one of its bites or horns.

Frightful Presence. Each creature of the kaiju’s choice within 1 mile of it and aware of it must succeed on a DC 17 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, with disadvantage if the kaiju is within line of sight, 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 kaiju’s Frightful Presence for the next 24 hours.

Bite. Melee Weapon Attack: +18 to hit, reach 10 ft., one target. Hit: 19 (2d8 + 10) piercing damage and 10 (3d6) fire damage. The target is grappled (escape DC 20). Until this grapple ends, the target is restrained, and the kaiju can't bite another target.

Horns. Melee Weapon Attack: +18 to hit, reach 10 ft., one target. Hit: 21 (2d10 + 10) bludgeoning damage and 10 (3d6) fire damage.

Claw. Melee Weapon Attack: +18 to hit, reach 15 ft., one target. Hit: 28 (4d8+10) slashing damage and 10 (3d6) fire damage.

Tail Whip. Melee Weapon Attack: +18 to hit, reach 15 ft., one target. Hit: 24 (4d6+10) bludgeoning damage and 10 (3d6) fire damage. If the target is a creature, it must succeed on a DC 20 Strength saving throw or be knocked prone.

Fire Breath (Recharge 5–6). The dragon head exhales fire in a 15-foot cone. Each creature in that area must make a DC 25 Dexterity saving throw, taking 59 (14d6) fire damage on a failed save, or half as much damage on a successful one.

Windstorm. The kaiju flaps its wings furiously, creating a 100 ft. cone of hurricane-force wind starting from any space it currently occupies. The wind lasts for 3 (1d6) rounds. For the duration, all flames in this region are extinguished, ranged attacks are impossible (except for those made by kaiju or siege weapons, which are rolled at disadvantage), and all creatures are deafened until they exit the area. Any medium or smaller creatures are knocked prone and pushed away from the kaiju 20 (1d4 x 10) feet. Any flying creatures are pushed away from the kaiju 70 (2d6 x 10) feet.

The kaiju 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. The kaiju regains spent legendary actions at the start of its turn.

Attack. The kaiju makes one attack (except bite).

Move. The kaiju moves up to half its speed.

Chomp. (Costs 2 Actions). The kaiju makes one bite attack or uses it’s swallow (if available).