Innate Spellcasting. The warlock’s innate spellcasting ability is Charisma. It can innately cast the following spells (spell save DC 15), requiring no material components:

At will: alter self, false life, levitate (self only), mage armor (self only), silent image

1/day each: feeblemind, finger of death, plane shift

Spellcasting. The warlock is a 17th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 15, +7 to hit with spell attacks). It regains its expended spell slots when it finishes a short or long rest. It knows the following warlock spells:

Cantrips (at will): eldritch blast, friends, frostbite, mage hand, minor illusion, prestidigitation, shocking grasp

1st–5th level (4 5th-level slots): armor of agathys, banishment, cone of cold, chromatic orb, ice storm, magic circle, misty step, scrying, stinking cloud, suggestion

Dark One’s Own Luck (Recharges after a Short or Long Rest). When the warlock makes an ability check or saving throw, it can add a d10 to the roll. It can do this after the roll is made but before any of the roll’s effects occur.

Mace. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 3 (1d6) bludgeoning damage plus 10 (3d6) cold damage.

Lightning Breath (3/Day). The warlock exhales lightning in a 30-foot-long line that is 5 feet wide. Any creature in the line must make a DC 13 Dexterity saving throw, taking 22 (4d10) lightning damage on a failed save, or half as much damage on a successful one.