Calamitas(Simulacrum)

Magic Resistance. Calamitas has advantage on all saving throws against all magical effects and spells.

Second Form. If Calamitas begins with less than 120 hit points on the start of her turn, she transforms into 2nd form, gaining 15 ft of walking and flying speed, and gains several actions.

Multiattack. Calamitas makes 5 Brimstone Ray attacks.

Slam. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 12(2d6 + 5) bludgeoning damage plus 12(2d8 + 5) piercing damage plus 9(2d8) fire damage. The target starts to burn for 1 minute, and the burn can't be extinguished by any nonmagical means. At the end of each of its turns, the target must succeed a DC 18 CON save, or take 14(2d8) fire damage. If the target drops to 0 hit points from this damage, the target crumbles to ash. On a success, the effect ends on the target.

Brimstone Ray. Ranged Spell Attack: +12 to hit, range 120 ft., one target. Hit: 14(2d6 + 7) fire damage. Miss: The projectile travels to maximum range, then splits into three smaller projectiles that re-target and attack three other creatures within 60 ft of it. The attack has a +6 to hit instead of a +12, and deals 7(2d6) damage instead of 14(2d6+7).

Brimstone Hellfire Ball(Recharge 4-6, 2nd form only). Calamitas fires a brimstone meteor at one target within 90 ft. The target must make a DC 18 DEX save or take 44(10d10) fire damage on a failed save, or half as much damage on a successful one.. The target starts to burn for 1 minute if it failed the save, and the burn can't be extinguished by any nonmagical means. At the end of each of its turns, the target must succeed a DC 18 CON save, or take 14(2d8) fire damage. If the target drops to 0 hit points from this damage, the target crumbles to ash. On a success, the effect ends on the target.

Summon Catastrophe(2/day, 2nd form only). Calamitas summons her brother, Catastrophe, who appears 60 ft from her and begins to attack.  While Catastrophe is alive, Calamitas has resistance against all damage.

Summon Cataclysm(2/day, 2nd form only). Calamitas summons her brother, Cataclysm, who appears 60 ft from her and begins to attack. While Cataclysm is alive, Calamitas has resistance against all damage.

Summon Soul Seekers(1/day, 2nd form only). Calamitas summons 5 Soul Seekers, which appear within 10 ft of her. The soul seekers orbit Calamitas and cannot move past 15 ft from Calamitas. While all soul seekers are alive, attacks against Calamitas have disadvantage and she has resistance against all damage.

Calamitas 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. Calamitas regains spent legendary actions at the start of her turn.

Move. Calamitas moves up to half her speed without provoking any oppurtunity attacks.

Strike. Calamitas makes a melee attack.

Ray Barrage(Costs 3 actions). Calamitas shoots a wall of Brimstone Rays. Every creature in a 120 ft line that is 15 ft wide must make a DC 18 DEX save. A target takes 18(4d8) fire damage on a failed save, or half as much damage on a successful one.