Warlock of the Shadow

Aberrant Dragonmark Mastery. The warlock can cast Detect Magic and Identify at will, without expending a spell slot or material components. His spellcasting ability is Intelligence (Spell save DC 18, +10 to hit with spell attacks).

Shadow Inured. The warlock has advantage on saving throws against being charmed or frightened. Additionally, when he deals necrotic damage, he regains hit points equal to half the necrotic damage dealt.

Multiattack. The warlock makes three attacks: one with his Shadow-Infused Wrench and two with his Shadow Bolts.

Shadow-Infused Wrench. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 10 (1d10 + 5) bludgeoning damage plus 13 (3d8) necrotic damage.

Shadow Bolt. Ranged Spell Attack: +10 to hit, range 120 ft., one target. Hit: 18 (3d8 + 5) necrotic damage. If the target is a humanoid, it must succeed on a DC 18 Wisdom saving throw or be frightened until the end of its next turn. 

Mark of the Abyss (Recharge 5–6). The warlock touches his Aberrant Dragonmark, tearing a temporary hole in reality. He summons 1d4 Maw Demons or 2d4 Dretches in unoccupied spaces within 30 feet. These demons act as allies to the warlock and remain for 1 minute or until they or the warlock die

Aberrant Shield. When the warlock is hit by an attack, he can use his reaction to release a pulse from his mark. He gains a +5 bonus to his AC against that attack and deals 10 (3d6) force damage to all creatures within 5 feet of him.

Legendary Resistance (2/Day). If the warlock fails a saving throw, he can choose to succeed instead.