Rathma Bone Spirit Necromancer Skills and Runes

Active Skills
Land of the Dead Frozen Lands Bone Spirit Astral Projection 1 Command Skeletons Enforcer 2 Devour Voracious 3 Blood Rush Metabolism 4 Revive Oblation
Passive Skills
Final Service Blood is Power Overwhelming Essence Serration

The build should start out runs by getting Revive minions up as soon as possible, ideally the maximum 10 per cast right out of the gate; naturally, this is necessary to maximize the 2-, 4- and 6-piece bonuses of the Rathma set, which at least partially hinges on reanimating the corpses of the fallen. The other half of the set mechanic can comfortably fall on Command Skeletons which should also be up at all times. Once (and only once!) you get the minions up and running, you want to spam Devour (we recommend that you bind its autocast via the Num Lock trick) throughout the run — if properly executed, you will get a massive streak of Bone Spirit resets once Land of the Dead is up and active. Do not neglect to use Revive during LotD uptime too, with several casts to ensure the rune Oblation procs your Blood is Power passive effect.

Another key point of this build lies between the interaction of Command Skeletons and Obsidian Ring of the Zodiac; by spamming the former (we recommend that you also bind its autocast via the Num Lock trick), the ring's power will produce its indispensable cooldown reduction and chop away at your vital Land of the Dead cooldown.

Befitting the namesake of the build, you will be using Bone Spirit as your nuke and main damage dealer. To maximize its damage potential, you will need to keep in mind the cubed Defiler Cuisses bonus and maintain your distance from the enemy, carefully freezing the encroaching foes, Blood Rushing into Oculus Ring procs and around the battlefield, all the while keeping your Gogok of Swiftness stacked for the vital cooldown reduction.

Your main damage dealer and namesake of the build is Bone Spirit, taken with the Astral Projection rune for the additional damage scaling for every target it passes through. The damage increases multiplicatively in 15% increments, and additively with itself — obviously, receiving no benefits on single target fights. The skill has three charges and a 15-second cooldown, reduced by a second every time a corpse is consumed; this gives you a massive burst window whenever Land of the Dead and its limitless corpse consumption is up and active. The projectile ignores collision with foes and terrain, and has a maximum projectile lifetime of 30 seconds, while also being able to seek out its own targets when untargeted, allowing you to mop up stragglers after a fight. Even so, it is highly recommended that you take the build's single target strengths in mind and prioritize high progression Elite enemies as much as possible.

Revive is an integral part of a Rathma setup, as the attacks of its minions will be responsible for roughly half of the cooldown reduction necessary to make Army of the Dead a reliable nuke. You will be taking the health-consuming rune Oblation for its ability to proc the cooldown reduction of the passive Blood is Power.

Command Skeletons is the other source of minion summons necessary to maximize the Rathma armor set bonus; on top of that, its active effect is a trigger for the Jesseth set weapon and offhand. With those two factors in mind, its inclusion is a necessity in this build. Since you will need to spam this skill (ideally via the Num Lock autocast trick), we recommend that you take the cheaper Enforcer rune to ease the strain on your resources.

Land of the Dead supplies you with an infinite amount of Corpses throughout its short duration, allowing you to unleash a string of nukes during its uptime due to the Corpse consumption (via Devour) reset mechanic of Bone Spirit. Note Land of the Dead's massive cooldown, which you will counteract with the spam of an Essence spender ( Command Skeletons) and its Obsidian Ring of the Zodiac interaction. The rune Frozen Lands will ensure the powerful Krysbin's Sentence proc on all enemies on the screen for an even better damage output, as well as a brief moment of absolute respite and safety due to its screen-wide crowd control.

Devour will be necessary for Corpse consumption and resets of your main nuke. We recommend that you Num Lock the autocast of this skill and once your minions are up in full numbers, not to relent from its spam until the end of the run. The recommended rune is Voracious, which will help counteract the steep Essence costs of spamming another cornerstone of this build — Command Skeletons. Its resource cost reduction aspects also has added damage reduction benefits via its interaction with the worn Cpt. Crimson set.

Last but not least, Blood Rush will be necessary for both mobility throughout the rift, and for another source of controlled health consumption (for the Blood is Power proc) via the health-costing rune Metabolism.

You will take a duo of damage bossting passives as a baseline. Serration is a straightforward addition that will simply increase your damage based on your distance from the target, encouraging you to play into the sniping tendencies of the build. And since this build relies on a cubed Reilena's Shadowhook for Essence reserve-based damage scaling, you will be taking the flat resource increase of Overwhelming Essence.

Blood is Power is the Necromancer's take on passives such as Evocation and Beacon of Ytar—along with the significant drawback of needing to lose your health reserve equivalent to trigger it. Since it counts off pre-mitigation values however, this passive will trigger from the very flow of gameplay (constant, high damage hits) in any meaningful Greater Rift progression difficulty, as well as from your own controlled health loss (via Oblation and Metabolism). With an overarching goal of reducing Land of the Dead downtime, Blood is Power finds a deserving place in your passive selection.

For your final passive slot we recommend Final Service — the Necromancer's cheat death, for a chance to evade a lethal outcome once every 60 seconds, along with a 10% healing proc per minion currently active.