This build has been tested in the 2.6.1 patch and Season 14 on PS4.
This build is quite possibly the end-all-be-all for the Pestilence set Corpse Lance focused builds. It is all about sheer mobility, allowing casting on the go with Devour being able to fire Corpse Lances via the 2 piece set bonus, and all skills revolve around ease of damage access and increased damage buffs. The use of Nayr's Black Death as a weapon or Cubed grants 100% increased damage for 15 seconds for every Poison skill used, a 500% damage increase for this build with all skills utilized in a timely rotation. Between the sheer damage, ready access to projectiles and stacked damage reduction and healing potential, this is a long ranged killer that can shred through mobs or hunt down elites in Rifts with ease.
Devour with Cannibalize is the main source of Essence generation and healing for the build, being able to fire off free Corpse Lances as well with the equipped damage type and rune effect making it double as a proper attack skill at the same time while recovering more health and Essence in bulk than most any other generator or healing option. With all the free corpses dropping and those left by slain enemies, the Necromancer should never be hurting for health or Essence at any point.
Bone Armor is the sole defensive skill for the build, but also maintains a healthy amount of use as a damaging skill thanks to the Nayr's 500% damage boost for skill rotation, the Dislocation rune making it count as Poison damage and the Stun effect proccing Krysbin's Sentence for 300% additional damage for follow-up attacks. The damage reduction also stacks with the damage reduction from the 4 piece set bonus, making it greatly aid the survivability of the build at all times.
The Ricochet rune for Corpse Lance grants it improved value for mobs, with the 1650% flat boost from the 6 piece bonus and the 500% Nayr's increase for obscene amounts of outgoing target seeking damage along with the aforementioned Krysbin's bonus of 300% to Stunned or Feared targets. In this regard, the 3300% boost to Bone Spear damage is more supplementary, but with the the Blighted Marrow rune granting 15% additional damage for every enemy it pierces through along with the other bonuses, and being the sole Essence spender for the build to freely spam it, it makes for a formidable secondary ranged attack.
The third ranged option is Bone Spirit, the constant corpse consumption from Corpse Lance and Devour making it so all 3 charges should be near constantly available for use and the 4000% base damage boosted by Nayr's and Krysbin's making it technically the Necromancer's strongest single target attack. The ability to Fear enemies near the target via the Panic Attack rune synchronizes with Krysbin's for further damage boosting, and with Pandemonium Loop to make the affected enemies explode for 800% weapon damage upon death, so chaining kills in larger mobs becomes all the easier.
All this is facilitated through the Command Golem with the Decay rune dropping free corpses every second thanks to the Moribund Gauntlets, making them constantly available for casting Corpse Lance or Devour as needed, or to feed the Golem itself at 30% increased damage per corpse consumed for 10 seconds. Keeping the Golem's cooldown reduced with the Golemskin Breeches in the Cube or worn helps keep the full 500% damage rotation for the build up as often as possible, and with an added bonus of another 30% damage reduction with the Golem present.
The passives help facilitate this structure, Commander of the Risen dead dropping the Golem's cooldown even further, Dark Reaping adding addtional 2% Essence and health gain when killing an enemy, Stand Alone granting 90% additional Armor with the Golem present, and Bone Prison adding a 30% chance to imprison enemies hit by Bone Spear and Bone Spirit, counting as an Immobilize effect for yet another way to proc Krysbin's Sentence.
There is an alternative for the build to speed up its mobility, mainly involving swapping the Ricochet rune on Corpse Lance for the Brittle Touch rune and using the Lost Time Phylactery with In-Geom. This would mark it as Cold damage instead and improve critical chance against enemies hit by it, and all those hits would proc the movement speed bonus on Lost Time and killing elite enemies would shred the cooldown on the Command Golem, letting it be used all the more often. A Hellfire Amulet with the Fueled by Death passive would help boost this even more. However this would drop the 500% damage bonus from Nayr's down to 400% instead, sacrificing damage for mobility.