The Necromancer is a boss encountered during Reclaim The Farm quest.
Strategy[]
The boss during the fight will summon undead and teleport away quickly. Itself does have no attacks and primarily uses undead to kill the player. It is highly recommended to have enough power to one hit the undead before the fight. It will summon group of undead each time it appears after teleporting but will not spawn more if there is already too much of them.
Weakness[]
The boss will stay briefly while summoning, you can predict it and strike before he appears. You also can stack up undead together so it easier to jump over them, then kill some enough for Necromancer to appear.