Fiendish Spirit

50 + 15 for each spell level above 6th

The fiend has advantage on saving throws against spells and other magical effects.

When the fiend drops to 0 hit points or the spell ends, the fiend explodes, and each creature within 10 feet of it must make a Dexterity saving throw against your spell save DC. A creature takes 2d10 + this spell's level fire damage on a failed save, or half as much damage on a successful one.

Magical darkness doesn't impede the fiend's darkvision.

The fiend makes a number of attacks equal to half this spell's level (rounded down).

Melee Weapon Attack: your spell attack modifier to hit, reach 5 ft., one target. Hit: 1d12 + 3 + the spell's level necrotic damage.

Melee Weapon Attack: your spell attack modifier to hit, reach 5 ft., one target. Hit: 1d8 + 3 + the spell's level slashing damage. Immediately after the attack hits or misses, the fiend can magically teleport up to 30 feet to an unoccupied space it can see.

Ranged Spell Attack: your spell attack modifier to hit, range 150 ft., one target. Hit: 2d6 + 3 + the spell's level fire damage. If the target is a flammable object that isn't being worn or carried, it also catches fire.