Black Frost

Potent Cantrips. Black Frost can add his spellcasting modifier (+5) to the damage he deals with any cantrip.

Altered Revivify. When Black Frost casts the revivify spell, it causes the resurrected creature to come back still suffering from an effect that killed it at the DM’s discretion. However, he does not need to use components to cast this spell.

Spellcasting. Black Frost is a 13th-level spellcaster. His spellcasting ability is INT (spell save DC 19, +11 to hit with spell attacks). Black Frost has the following spells prepared:
Cantrips (at will): ray of frost, toll the dead, message, spare the dying, eldritch blast
1st level (4 slots): mage armor, cure wounds, inflict wounds, silvery barbs
2nd level (3 slots): misty step, snilloc's snowball swarm, web
3rd level (3 slots): vampiric touch, revivify, haste
4th level (3 slots): dimension door, blight, sickening radiance
5th level (2 slots): cone of cold, contagion
6th level (1 slot): wall of ice, flesh to stone
7th level (1 slot): mordenkainen's sword

Scepter of Tomfoolery. Black Frost holds the Scepter of Tomfoolery, a legendary Fey artifact that increases his spell save DC and spell attack modifier by +1. It also allows him to cast the following spells:
counterspell (at will), summon fey (1/day), temporal shunt (1/day), otto's irresistible dance (1/day), tether essence (1/day)

Evasion. When Black Frost is subjected to an effect that allows him to make a Dexterity saving throw to take only half damage, he instead takes no damage if he succeeds on the saving throw, and only half damage if he fails.

Mabufula (recharge 6). All creatures in a 30 foot cone must succeed on a DC 19 Constitution saving throw. Upon a failure, a creature in the cone takes 6d6 cold or necrotic damage, half upon a success with no additional effect. If the damage dealt upon a failure is cold, the creature has its movement halved until the end of its next turn and cannot use its reaction; if the damage dealt is necrotic, the creature has disadvantage on the next attack roll or saving throw that it makes.

Jester's Tinsel. Ranged Spell Attack: +11 to hit, range 80/150 ft., 1 target. Hit: 25 (4d10 + 5) force damage.

Cunning Action. Black Frost can take the dash, disengage, or hide actions as a bonus action.