Xul is a Melee SpecialistHero from Diablo universe. He is the same Necromancer the player can control in Diablo II. Accordingly to his in-game lore and interactions with the other Heroes, Xul has been transported into the Nexus after the events of Diablo II.
From the recesses of the eastern jungles comes a man cloaked in mystery. As a member of the secretive Priests of Rathma, or the Necromancers, Xul fights to preserve the delicate balance between order and chaos. Using powerful death magic, Xul will sap the strength of his enemies, block their escape, and direct his spectral scythe with lethal accuracy. Those who fall before the Necromancer find no peace even in death, rising again as skeletal servants bound to do their master’s bidding.
Bone Prison spawns 2 Skeletal Warriors. These do not count towards Xul's Raise Skeleton maximum. Quest: Spawn 80 Skeletal Warriors. Reward: While fixating on an enemy, Skeletal Warriors gain 50% Movement and Attack Speed.
Xul can provide a solid frontline in the form of his debuffs, with Cursed Strikes (and many of its talents) and Skeletal Mages. However, Xul's synergy with Kel'Thuzad lies with Bone Prison, which, once cast, will give Kel'Thuzad enough time to prepare his combos as soon the opponent is rooted.
As another good early game pushing Hero, Xul offers Varian troubles towards the beginning of matches. When combined with Bone Prison’s root and Cursed Strikes attack speed slows, Varian can be almost completely shut down if he doesn’t pick his fights correctly.
In a similar fashion to Azmodan, Xul's ability to summon minions results in Malthael having extra sources of heal through Soul Rip. Since Malthael's damage relies more on his trait than basic attacks, he can stay from a safe distance, avoiding Xul's gap closers (Cursed Strikes and Bone Prison).
(Patch July 11, 2017) Note:Xul has received updated visual effects to coincide with Talent updates.; Bone Visage Xul, Classic Bone Visage Xul, Royal Bone Visage Xul, Rusted Bone Visage Xul, Skeletal Bone Visage Xul, Reaper Necromaster Xul skins added.