Warlock of the undead

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: detect magic, jump, levitate, mage armor (self only), speak with dead

1/day each: arcane gate, true seeing

Spellcasting. The warlock is a 14th-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): chill touch, eldritch blast, guidance, mage hand, minor illusion, prestidigitation, shocking grasp

1st–5th level (3 5th-level slots): armor of Agathys, arms of Hadar, crown of madness, phantom steed, contact other plane, blindness/deafness, dimension door, bane, greater invisibility, cloudkill, vampiric touch, animate dead.

Dagger. Melee or Ranged Weapon Attack: +5 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 4 (1d4 + 2) piercing damage.

Necrotic Husk.  When the warlock would be reduced to 0 hit points, the warlock can use their reaction to drop to 1 hit point instead and cause their body to erupt with deathly energy.  Each creature of their choice that is within 30 feet of the warlock takes necrotic damage equal to 2d10 + 14.  The warlock then gains 1 level of exhaustion.  This ability can be used once every 1d4 long rests.