Sources
CR
Type
Size
Alignment
Movement

Warlock of the Fiend

Medium Humanoid (any race), Any alignment

Armor Class 12, 15 with mage armor
Hit Points 78 (12d8 + 24)
Speed 30 ft.
STR
10
+0
DEX
14
+2
CON
15
+2
INT
12
+1
WIS
12
+1
CHA
18
+4
Saving Throws WIS +4, CHA +7
Skills Arcana +4, Deception +7, Persuasion +7, Religion +4
Damage Resistances slashing, from nonmagical attacks not made with silvered weapons
Senses darkvision 60 ft., passive Perception 11
Languages any two languages (usually Abyssal or Infernal)
Challenge 7 (2,900 XP)

Traits

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.

Spellcasting

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, fire bolt, friends, mage hand, minor illusion, prestidigitation, shocking grasp

1st–5th level (4 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.

Lore

Warlocks of the fiend gain their powers through magical pacts forged with archfiends of the Lower Planes. These warlocks often keep imps or quasits as companions, and they tend toward extremes of behavior: consorting with fiend-worshiping cultists or dedicating their lives to destroying fiendish cults.