Cold Drain Essence Reaper

A channeled attack that deals ongoing Cold/Vitality damage while leeching health from the target. Its Hungering Reach modifier increases the number of enemies hit (10 points is the soft breakpoint). Bind the Amatok devotion's Blizzard proc here (100% chance on crit).

A summoned spectral blade companion that adds extra attacks. Bind the Rhowan's Crown devotion's Elemental Storm proc here.

An always-on debuff aura. The base skill only lowers enemy offensive ability and total speed, but its Night's Chill modifier adds Pierce/Cold/Poison-Acid/Vitality resistance reduction on top — the build's primary resistance-shred source, applying with almost no upkeep.

A curse that lowers the target's damage output, while also dealing Cold/Vitality Decay damage and applying Confusion.

A powerful buff granting a large chunk of health and offensive ability — the author calls it "hands down very powerful."

A Necromancer-exclusive skill that the author calls the key investment behind this build's damage, which is also why Cunning gets prioritized among the attributes.

An instant heal-and-buff, used as an emergency safety net.

A Necromancer defensive skill that transfers a portion of incoming damage to a single marked enemy at 200% — only one target can be marked at a time, it's not an area effect. It doesn't reduce enemy resistance either.

• ▸Start as Necromancer and put 1 point at a time into Drain Essence while leveling. Pick Nightblade as your secondary around level 10.
• ▸From roughly level 14, use vendor medals to cover resistance/health, and once your blacksmith is secured, craft 2x Wardstone for the medal and amulet slots. In Act 1's Witchmare, chase the quest-reward Slith Primal Ring.
• ▸After defeating Warden Krieg, head into Forgotten Gods for a movement augment. From there, chase Korvan armor (around Cairn Docks) and Gargoyle Waistguard (Astral Fields, the area right before the Korvaak fight); once you have both, switch over to investing in the Necromancer's Decomposition.
• ▸Farm Magi Mantle from the Magi at Magi's Court in the Tomb of the Heretic (a quest-gated dungeon — doing this after Korvaak works well).

• ▸Build the endgame around the Chillwhisper set (crafting it needs Celestial Lotuses). Even the budget version reaches SR 26-27.
• ▸Belt: Gargoyle Waistguard. Amulet/medal: start with Wardstone and upgrade to endgame pieces later.
• ▸Prioritize a weapon with doubled-up Cold damage (base Cold damage plus an Elemental/Cold affix).
• ▸Gloves: aim for cast speed (an "of Celerity" suffix). Boots: craft for health and resistances.
• ▸Pants: farm Solael Guardian for an "Impervious" prefix roll. The rest can be targeted in any order, but leave Magi Mantle for last.

• ▸Keep Drain Essence trained on your target, using Hungering Reach to widen how many enemies it hits.
• ▸Maintain Blade Spirit while Ill Omen cuts enemy damage output and Mark of Torment transfers incoming damage to a single marked target.
• ▸Drain Essence can't break objects, so shift-move or a movement augment to route around them.
• ▸Hit Pneumatic Burst for an instant heal when incoming damage spikes.

Veil of Shadow's Night's Chill modifier (reducing Pierce/Cold/Poison-Acid/Vitality resistance) and the Murmur devotion handle resistance shred; both are tied to an aura/curse, so upkeep is nearly automatic. Ill Omen stacks on top as a separate enemy-damage-reduction debuff, not a resistance shred. Fill your own resistances to cap with gear and augments.

Drain Essence can't break objects, so some farming routes require detours. Fully crafting the Chillwhisper set needs Celestial Lotuses, and the budget setup is a bit squishy. Patch 1.3 brought a minor Drain Essence nerf, but commenters report it's barely noticeable in practice.

Farm Cairn Docks for Korvan armor, the Astral Fields, the area right before the Korvaak fight for Gargoyle Waistguard, Magi's Court in the Tomb of the Heretic for Magi Mantle, and reset-buy the Vinelton vendor for Living Rings and similar pieces.