Otherworldly Patron: Arch Lich

Your pact is made with a powerful commander of undeath. While safely tucked away somewhere Carceri, the perpetually plotting lich grants you some of its necromantic power in return for strange and unexplained favors. The secret plans of the lich are known only to them, and what little knowledge they do allow their subordinates is sure to be incomplete or obfuscated in some way. This does not concern you. Your only concern is the raw power necromancy can give you. Control over life and death. Each dark spell or ritual you pry from your patron brings you one step closer to unraveling the secrets of immortality. With this dark deal made only two things in life become certain: there will be death, and it will not be the end. 

Expanded Spell list:                                                                                                                             Class Features: 

Spell level                                                                                                                                              Class Level:

1st          Cause Fear, Chill Touch                                                                                                      1st          CarrionFeeder

2nd         Blindness/Deafness, Gentle Repose                                                                                6th          Flesh Sculptor

3rd          Animate Dead, Vampiric Touch                                                                                        10th        Unearthly Resolve

4th          Phantasmal Killer, Evard's Black Tentacles                                                                    14th        Mantle of Undeath

5th          Raise Dead, Contagion 

Carrion Feeder

Once per turn, killing a creature with a spell grants you temporary hit points equal to twice the spell's level (must be first level or higher). You gain triple the temporary hitpoints if the spell was from the necromancy spell school. You keep these hitpoints until they are used, or until a short or long rest. 

Flesh Scluptor

When you create undead with a necromancy spell you can select one of the following options to imbue it with:

Flesh Shield

Your undead gains temporary hit points equal to twice your warlock level. 

Bone Blade

You can add your proficiency modifier to attack rolls made by your undead. For the purposes of overcoming immunity and resistance to nonmagical attacks and damage, attacks made by the undead are considered magical. 

Undead Servant

Your undead takes on the appearance of a living humanoid. The illusionary effect causes the undead to appear like it was when it was alive. The undead still cannot speak and exudes a rotting stench. A DC 12 investigation check will reveal it to be undead. 

Unearthly Resolve

You gain 2 hit points for each warlock level you have, and 2 more each time you gain a level in warlock. You have permanent disadvantage on constitution and strength checks. You appear more gaunt and pale.  

Mantle of Undeath

Once per day as an action activate the Mantle of Undeath which lasts for 10 minutes. All creatures that can see you must make a DC 15 wisdom save or become afraid of you. You are resistant to nonmagical bludgeoning, piercing, and slashing damage, as well as necrotic damage. You can move over difficult terrain as if it were normal.