Necromancer

A necromancer's strengths are in bolstering undead, summoning or raising undead minions (which they can control up to a number of a large mob) and being able to cast a vast repertoire of various necromancy spells. They are strong spell casters but are not durable in physical combat. A necromancer should primarily be used for crowd control, able to curse the enemy while animating different undead to occupy the enemy while their teammates continue to sustain a mass of dead bodies for you.

Undead companion

 

You can create undead as your companion. With a casting time of 8 hours, you can create one undead. You can create a number of undead equal to double your character level but you can only have the amount of undead CR combine to be half your character level. You will need the corps or what ever you need to create the undead. Ex: zombie, humanoid corps. Phantom Warrior: spirit of dead people. Talk to your DM on what you can make, such as you can't create a Vladimir Horngaard using an average human corps. Your undead use their statist when they are alive, such a fighter zombie can still use multi attack and a wizard can still cast spell. Some of the ability may no longer be able to use, such as Divine Intervention, they're dead so they can no longer call upon their god. All of your created undead have half the intelligent, wisdom, and charisma as when they were living, rounded up. 

You can no longer cast spells like Animate Dead or Create Undead or anything similar to it. 

Undead nature

Undead such as zombie or skeleton won't attack you, unless they're ordered to. High intelligent undead will not attack you at first and your Persuasion check against undead have advantage. You can sense undead with in 120 feet of you, you cannot tell what it is or where it exactly is but you know there is undead in a general direction. 

Undead Fortitude

Necrotic touch

 You can spend 2 + the spell level to make a necromancy spell to deal maximum damage. Also, your unarm strike deal an additional 1d6 necrotic damage. 

Gate to death

You are now immune to necrotic and cold damage. You are immune to the poison condition and are now vulnerable to fire damage. 

When you die and you failed your Undead Fortitude, your soul comes out of your body and you turn into a ghost. Your statistic is replaced by ghost except for you wisdom, intelligent and charisma scores. You cannot be revived during this time unless you are within 1ft of your body. You can also parasitic on to one of your created undead. As an action, you can put your ghost into one of your created undead. Your statistic now is replaced by the undead except for your intelligent, wisdom, and charisma score. You can remain as this state until you use an action to move out or the undead die. If you move out, the undead you just parasitic on drop to 0 hit points. You can remain as a ghost for 300 years which then you are a ghost forever and cannot be turn back to how you were unless by a wish spell. 

You can now cast Finger of death once a day with out spending a spell slot, you can now have the amount of undead more than double your level through other spells. You can also, as an action, see and hear through one of your created undead. You can control it to move as if you are in it's body. During this time, you are paralyzed. This last until you use an action to stop it or the undead die.