LoD Blood Nova Necromancer Skills and Runes

Active Skills
Siphon Blood Power Shift Death Nova Blood Nova 1 Simulacrum Blood and Bone 2 Blood Rush Transfusion 3 Bone Armor Dislocation 4 Frailty Aura of Frailty
Passive Skills
Swift Harvesting Eternal Torment Spreading Malediction Stand Alone

The build starts runs by activating Bone Armor, cast in range of an early pack of (ideally lower threat) monsters to maximize its damage reduction bonuses. You will also activate Frailty, but need do so only once per run due to the permanent bonus of Aura of Frailty. The build relies on Death Nova Blood Nova for the entirety of its damage output; you will be casting the skill through a combination of manual use as well as constant channeling of Siphon Blood and the subsequent guaranteed proc of Iron Rose. The near-constant channeling of an Essence generation skill allows you to maintain your Essence reserve high and enjoy high uptime of of Aquila Cuirass. Your Simulacrums, made permanent with the use of Haunted Visions, will provide a large chunk of your damage; ensure they are up for the Physical cycle of Convention of Elements for a massive burst of damage.

The focal point of the build is Death Nova, whose damage you will amplify through various means — elemental damage on gear (see this build's gear page for more information), the interaction between Funerary Pick and Siphon Blood, and skill-specific items like Bloodtide Blade and Iron Rose. The latter is especially important, since it practically locks you into the health-spending Blood Nova rune. You can easily mitigate rune's blood cost however, and even gain superb damage amplification bonuses from Siphon Blood Power Shift and its interaction with Funerary Pick.

Bone Armor brings some much needed damage reduction to the build, extended even further by the equipped or cubed Wisdom of Kalan. It is recommended that you take the rune Dislocation for an extra on-demand proc of Krysbin's Sentence from the 2-second stun. Alternatively, you can slot Harvest of Anguish for the improved mobility throughout the rift.

Simulacrum will be taken with the rune Blood and Bone in order to triple your damage output, as both clones will duplicate your Blood Novas. The minions will be made permanent (rather than the fleeting duration they have by default) with a worn or cubed Haunted Visions amulet.

In order to more efficiently scout out rift levels, plan engagements, or even outright skip unfavorable fights, you will be using the Necromancer's solitary movement tool — Blood Rush. Couple it with the Transfusion rune to regain lost health from Blood Nova spam, or the toughness rune Potency for a brief survivability spike upon use.

Lastly, you will be taking a Curse into the build to improve your overall damage output. For AoE convenience, it is recommended that you take an automatically applying rune such as Frailty Aura of Frailty, whose radius mimics the caster-centric Blood Novas. Note the rune's synergy with Pickup Radius on gear, and try to obtain it in the Secondary Stats of your items.

Since this falls into the category of low summoning builds, you can make great use of the Stand Alone passive and its massive Armor bonuses.

Two interconnected passives — Eternal Torment and Spreading Malediction — will work off each other, with the former making the curse spread by the Aura of Frailty last indefinitely, and the latter — increasing your damage for each afflicted enemy with no apparent cap. Note that you can viably alternate Eternal Torment to Final Service if you don't fancy pushing Greater Rifts without a cheat death at your disposal.

Swift Harvesting is a straightforward addition to the build, as you inflict all of your damage through Iron Rose's Blood Nova procs via Siphon Blood, and this passive amplifies the latter's attack speed by a significant margin.