Dark One's Own Luck (Recharges after a Short or Long Rest).

When the goblin 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.

Innate Spellcasting.

The goblin'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

Nimble Escape.

The goblin can take the Disengage or Hide action as a bonus action on each of its turns.

Spellcasting.

The goblin 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, fire bolt, friends, mage hand, minor illusion, prestidigitation, shocking grasp
1st-5th level (4 5th-level slots): banishment, burning hands, flame strike, hellish rebuke, magic circle, scorching ray, scrying, stinking cloud, suggestion, wall of fire

Actions

Mace.

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

Booyahg Slave of the Fiend