The Necromancer

Your patron is a powerful necromancer or commander of the undead. Your patron might be one of the notable necromancers such as Aumvor the Undying, Kazerabet, Sammaster the Mad, Shoon VII, Sumulael, Szass Tam, Velsharoon, Xzar, Ysuran Auondril, Zallanora Argentresses, or perhaps an unknown entity that rules over hordes of the undead. Your patron gives you sway over the undead and powers to control the fallen. 

Expanded Spell List

The Necromancer lets you choose from an expanded list of spells when you learn a warlock spell. The following spells are added to the warlock spell list for you.

Necromancer Expanded Spells

SPELL LEVEL	SPELLS
1st	command, false life
2nd	blindness/deafness, enlarge/reduce
3rd	speak with dead, phantom steed
4th	arcane eye, death ward
5th	antilife shell, cloudkill

Undead Chain Master

At first level, you gain the ability to summon an undead servant to aid you. As an action, you can summon a Crawling Claw that is friendly to you and your allies. You can command the undead to perform simple tasks for you that is within it's abilities, such as fetching objects or opening doors. In combat the undead shares your initiative but goes immediately after you and takes the dodge action on it's turn, unless you command it otherwise using your bonus action. The undead lasts for 1 hour, until you go unconscious, you unsummon it, or die. Additionally, the undead is added to your available choices with the pact of the chain feature when you use the find familiar spell, when summoned this way it is still an undead. 

Undead Companion

Starting at 6th level, you can tap into the magic of the underworld to summon an undead to be bound to you. As an action, you can summon the undead, which manifests in an unoccupied space of your choice that you can see within 20 feet of you.

The undead is friendly to you and your companions and obeys your commands. See its game statistics in the Undead Companion stat block, which uses your proficiency bonus (PB) in several places. When you summon the undead, choose the creature’s form: Glutton, Ravager, or Hawker. The creature resembles an undead creature with the chosen form, which determines certain traits in its stat block. 

In combat, the undead shares your initiative count, but it takes its turn immediately after yours. It can move and use its reaction on its own, but the only action it takes on its turn is the Dodge action, unless you take a bonus action on your turn to command it to take another action. That action can be one in its stat block or some other action. If you are incapacitated, the undead can take any action of its choice, not just Dodge.

Once you summon the undead, you can’t do so again until you finish a long rest. The undead remains for a number of hours equal to your proficiency bonus, until it is reduced to 0 hit points, until you use this feature to summon the undead again, or until you die. Anything the undead was wearing or carrying is left behind when the undead vanishes.

Undying Bond

When you reach 10th level, your connection with the undead intensifies. Undead that are friendly towards you and are within 60 feet of you gain temporary HP equal to 5 + your warlock level and resistance to non-magical bludgeoning, slashing, and piercing damage that aren't silvered. Additionally, you gain resistance to necrotic damage. 

Summon Titan

When you reach 14th level, you learn to fabricate gruesome horrors of the underworld into being. When you use your Undead Companion feature, you can instead choose to summon an undead Titan using its game statistics in the Undead Titan stat block.