Arc Comet Blood Mage Endgame Build

Introduction

This guide has been fully updated for The Last of the Druids, Fate of the Vaal League (Patch 0.4.0).

The Arc Comet Blood Mage Witch is an insane speed-farming build, capable of exploding entire screens of enemies while flying through maps. Lightning-Infused Arc chains through enemies, triggering Fire-Infused Comet from Cast on Critical to deal devastating damage in a massive area. Orb of Storms and Frost Wall supplements damage output for more triggers to instantly destroy pinnacle bosses. Rain down great balls of fire with this top-tier endgame build!

This build guide assumes you have reached endgame maps around Level 65. If you have not yet completed the campaign, follow the Arc Leveling Build Guide.

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Strengths and Weaknesses

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Build Mechanics

Infinite “Mana”

Mana is a primary concern for the typical spellcaster. The Mana costs of Skills continue to grow as you increase skill gem levels, and most support gems multiply costs even further. To achieve enough Mana sustain for these high costs, a considerable investment must be made to gain Maximum Mana and Mana Regen using Skill Points and gear affixes.

The Blood Mage Ascendance node, Vitality Siphon, enables Spell damage to be leeched as Life to provide an endless source of Life sustain. This enables the Blood Mage to utilize Blood Magic, removing mana entirely to only pay skill costs with Life.

Life is also recovered by Life Remnants, granted by Sanguimancy. These life globes spawn primarily from killing enemies and can overflow Maximum Life to 1.5 times the normal amount. Continue to absorb Life Remnants while clearing groups of enemies for additional sustain.

Survivability

The Blood Mage ascendancy nodes, Grasping Wounds and Crimson Power, significantly boost survivability. Equip a Chest Armor with up to 1,200 Energy Shield to gain just as much Maximum Life. A high EHP (Effective Hit Points) is obtained through a combination of both Life and Energy Shield.

Soul Tether provides a significant boost in survivability, and it should be your first expensive purchase. The excess Spell Leech from Vitality Siphon is applied to Energy Shield for instant recovery while taking hits during combat. The Lose Maximum Energy Shield Per Second affix must be replaced by a Vaal Cultivation Orb, without adding a Lose Maximum Life Per Second affix.

Do not equip Atziri’s Acuity, as the instant Leech prevents excess Leech from being applied to Energy Shield.

Infusions

Arc, Comet, and Frost Wall consume Infusions to greatly empower their damage.

Lightning Infusions are generated by Orb of Storms after it expires from casting all its bolts or the duration ends. The orb limit is increased to three by Overabundance II and Secrets of the Orb in the Passive Tree, and then Unleash creates all three orbs from a single cast.

Snap is another lucrative source of Infusions. Ensure you have Extra Fire Damage on your Staff to Ignite enemies, in addition to applying Shock with the base Lightning Damage of Arc and Orb of Storms. After enemies die, their Ignited and Shocked corpses can be snapped to generate Lightning and Fire Infusions. Cooldown Recovery II and Khatal’s Rejuvenation grant increased Cooldown Recovery Rate to allow Snap to be cast often. Make sure you do not have any Extra Cold Damage in your build, as Frozen enemies shatter and cannot be snapped.

Damage and Critical Hit Chance

Increasing damage output is extremely important for this build to function, as it effectively scales quadratically. Damage increases cause your Spells to hit harder, which generates more Energy for Cast on Critical to trigger Comet more often. Dealing more damage also has a higher chance to apply Shock and Ignite to generate Infusions with Snap.

Aim for at least 50% Critical Hit Chance for Arc. Sunder the Flesh sets the base Critical Hit Chance from 9% to 15%, so you only need +234% increased Critical Hit Chance to get started. Ambush supports Arc to double its Critical Hit Chance to guarantee it on the first hit against enemies. Anoint Preemptive Strike on your Amulet to also gain 100% increased Critical Damage Bonus against Enemies that are on Full Life. This setup allows the high base damage of Lightning-Infused Arcs to instantly kill most enemies in one hit and trigger Comet from Cast on Critical consistently.

Scale damage output not only for offensive, but also for defense. Increasing damage causes a higher Leech of Life and Energy Shield through Vitality Siphon to sustain against incoming damage.

Ensure you prioritize the following stats in this build, as they make a significant difference in performance.

• Level up to allocate additional Passive Skill Points for damage and Energy generation nodes.
• Skill Levels provide the most significant damage upgrades with a Level 21 Corrupted Arc Skill Gem, Staff (+6 affix and +1 rune), Amulet (+3), and Prism of Belief Diamond Jewel (+3 Arc).
• You should also obtain high Spell Damage, Elemental Damage, and Critical Damage Bonus values on your Staff and Rare Jewels. Refer to the Gear section for more details on stat priority.

Life Cost Management

The default setup in this guide is designed to help players get started with the build without encountering resource issues. You need enough Maximum Life to rapidly cast skills, and damage needs to be high enough to leech the Life Costs back. Therefore, suggested supports don’t have big cost multipliers. Increased Cost Efficiency is also granted through socketables inserted into your Gloves (Tecrod’s Gaze) and Helm (Idol of Eeshta).

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Skill Rotation

Follow the basic skill rotation below to clear groups of enemies in maps:

1. When starting a map without any Lightning Infusions, cast Orb of Storms to Unleash three orbs at once. The orb limit is increased by Overabundance II and Secrets of the Orb in the Passive Tree. Collect Lightning Infusions after the orbs expire.
2. Cast Lightning-Infused Arc to deal damage and trigger Fire-Infused Comet from Cast on Critical.
3. After enemies are killed, cast Snap on their Shocked and Ignited corpses to generate Lightning and Fire Infusions.
4. Cast Blink (optional) to traverse quickly.
5. Continue to cycle Arc and Snap to maintain Infusions. If you are dealing enough damage and moving fast with Blink, casting Orb of Storms is not always necessary.

Execute the steps below to optimize damage against bosses:

1. For maximum damage against Pinnacle and Citadel bosses, swap Magnified Area II to Living Bomb in the Cast on Critical setup for Fire Infusions. This Gem swap should not be necessary against Map bosses if you already have appropriate damage.
2. If you need Lightning Infusions, cast Orb of Storms before the fight and wait for them to expire.
3. Cast Sigil of Power from a Chiming Staff equipped in Weapon Set 2 to buff damage.
4. Switch back to Weapon Set 1 (Skills can be set to automatically swap).
5. Cast Elemental Weakness to reduce the Resistance of the boss. Elemental Weakness can be pre-cast before a boss spawns if supported by Cursed Ground.
6. Cast Orb of Storms to Unleash three orbs at once.
7. Cast Frost Wall immediately as the boss spawns.
8. Spam Arc to deal damage and trigger Comet from Cast on Critical.
9. Recast Frost Wall after they explode.

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Video Guide

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Skill Gems, Spirit Gems, and Support Gems

The Arc Comet Blood Mage utilizes the following Skill Gems, Spirit Gems, and Support Gems. Gem Sockets are listed in order of priority.

Equip a Chiming Staff in Weapon Set 2 to unlock Sigil of Power, which provides a damage buff against bosses. Ensure you set all your other skills to only be used with Weapon Set 1, so you automatically swap back.

Against pinnacle bosses, swap Magnified Area II socketed in Cast on Critical to Living Bomb (Level 3) to generate Fire Infusions. Ensure Living Bomb is inserted in a socket before Comet (highest Level possible).

All Skill Gems should be leveled as high as possible, except for Living Bomb, which can be kept at the minimum of Level 3.

Rakiata’s Flow is the final expensive upgrade and is not included in the Skill Gem setup below. After you obtain Rakiata’s Flow, replace the Lightning Mastery socketed into Arc.

Blink is optional if you enjoy speeding through maps. An additional 51 Spirit is needed from a corrupted Helmet and/or an Amulet. Apply quality to Cast on Critical to reduce its Spirit Reservation to 91. Cooldown Recovery II and Khatal’s Rejuvenation (socketed into Snap) enable Blink to be cast often for rapid mobility.

Atziri’s Impatience is currently not removing Life or Energy Shield when supporting Blink, so it can be equipped instead of Cooldown Recovery II until it is bug fixed.

Perfect Jeweller’s Orb priority on Skill Gems: Arc > Cast on Critical > Orb of Storms > Snap > Frost Wall > Elemental Weakness.

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Ascendancy

Blood Mage is the recommended Ascendancy for the Lighting Warp Witch. The chosen Ascendancy can be switched within the base class by repeating your highest trial completion.

Allocate the Ascendancy nodes for Blood Mage in the following order:

1. Sanguimancy and Vitality Siphon — These nodes need to be allocated together to be able to sustain the Life costs of Skills with Spell Leech.
2. Sunder the Flesh — Sets the base Critical Hit Chance of Spells to 15%.
3. Grasping Wounds — The delayed damage taken drastically improves survivability against getting one-shot by allowing you time to recover Life.
4. Crimson Power — Energy Shield granted by your Body Armor also provides Maximum Life, which can amount to 1000+.

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Passive Skill Tree

In the Passive Skill Tree, utilize attribute nodes to fulfill any Intelligence and Dexterity requirements, and then allocate the remaining points to Strength for Maximum Life.

Secrets of the Orb is obtained to grant the third orb limit, in addition to Overabundance II. Essential damage increases are allocated early. Blood Magic is eventually necessary to remove Mana costs when your Skill Levels are high. Use the progression bar in the Skill Tree tool for the allocation order of nodes.

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Gear

The preferred gear for the Arc Comet Blood Mage is listed below with affixes ranked in order of importance. Prioritize Rare Items with the correct base stats and beneficial explicit affixes. Recommended Unique Items are listed below the Rare Item table.

Rare Items

Equipment Slot and Base Stats	Affix Priority	Notes
Staff	Do not obtain any Extra Cold Damage, as Frozen enemies shatter and prevent Snap from being cast on their corpses. 1. Level of all Spell Skills (applies to both Lightning and Cold Spell Skills) 2. Extra Fire Damage (applies Ignite to enemies to generate Fire Infusions from Snap) 3. Extra Lightning Damage 4. Spell Damage with Spells that cost Life or Spell Damage 5. Critical Hit Chance for Spells 6. Critical Spell Damage Bonus 7. Cast Speed	Socket(s) Priority: 1. (Expensive) Hedgewitch Assandra’s Rune of Wisdom for +1 to Level of all Spell Skills 2. (Cheap) Greater Desert Rune for 10% Extra Fire Damage
Helmet — Energy Shield	1. Spirit (affix from corruption) 2. Maximum Life 3. Critical Hit Chance 4. Resistances, Attributes, or Item Rarity 5. Maximum or Increased Energy Shield	Socket(s) Priority: 1. Any Rune that grants Resistance if not yet capped. 2. Idol of Eeshta for 12% Increased Cost Efficiency
Body Armor — Energy Shield	1. Maximum and Increased Energy Shield (prioritize the highest total Energy Shield to also gain Maximum Life from Crimson Power) 2. Resistances or Attributes	Socket(s) Priority: Greater Iron Rune
Gloves — Energy Shield	1. Maximum Life 2. Critical Damage Bonus 2. Resistances, Attributes, or Item Rarity 2. Maximum or Increased Energy Shield	Socket(s) Priority: 1. Any Rune that grants Resistance if not yet capped. 2. Tecrod’s Gaze for 25% increased Life Cost Efficiency
Boots — Energy Shield	1. Movement Speed 1. Maximum Life 2. Resistances, Attributes, or Item Rarity 2. Maximum or Increased Energy Shield	Socket(s) Priority: 1. Any Rune that grants Resistance if not yet capped. 2. Farrul’s Rune of the Chase for 5% Increased Movement Speed
Amulet	1. Spirit 2. Level of all Spell Skills 3. Maximum Life and Percent Maximum Life 4. Percent Maximum Energy Shield 5. Critical Hit Chance or Critical Damage Bonus 6. Cast Speed 7. Resistances, Attributes, or Item Rarity	Anointment Priority: 1. Preemptive Strike (offensive) 2. Patient Barrier (defensive) Quality: Flesh Catalyst
Rings	1. Maximum Life 1. Cast Speed 2. Resistances, Attributes, or Item Rarity	Quality: Flesh Catalyst
Belt — Heavy (replaced by Soul Tether with no Life/Energy Shield loss)	1. Charm Slots (at least 2) 2. Maximum Life 3. Resistances or Attributes 4. Flask Life Recovery Rate 5. Charm Effect Duration 6. Stun Threshold	–

Unique Items

The following recommended Unique Items for the Lightning Warp Comet Blood Mage are listed below:

• Soul Tether applies excess Life Recovery from Leech to Energy Shield, enabling rapid recovery from Vitality Siphon while taking hits in combat. Only equip if the Lose Maximum Energy Shield Per Second affix is replaced by a Vaal Cultivation Orb, and there is no Lose Maximum Life Per Second affix. Faster Life Leech is an ideal replacement affix, but not required.
  • Do not equip Atziri’s Acuity, as the instant Leech prevents excess Leech from being applied to Energy Shield.

Jewels

The beneficial affixes for Jewels are listed below, ranked in order of importance. Prioritize Rare Jewels with two prefixes and two suffixes.

• Prefixes
  1. Increased Energy Shield
  2. Magnitude of Ailments (for Shock), Spell Damage, Elemental Damage, or Area of Effect
• Suffixes
  1. Critical Damage Bonus, Critical Spell Damage Bonus, Critical Strike Chance, or Critical Strike Chance for Spells
  1. Cast Speed

In addition to the Rare Jewels, the following Unique Jewels are recommended for this build.

• Prism of Belief Diamond (limit 1): 1-3 Levels of Arc (for map clearing) or Comet (for boss killing) is a priority to increase damage output.
• Heart of the Well Diamond (limit 1): For the prefixes, obtain Extra Fire Damage to Ignite more often and Increased Cooldown Recovery Rate to speed up gameplay with Snap and Blink. The suffixes can contain any combination of Critical Damage Bonus, Critical Spell Damage Bonus, Critical Strike Chance, or Critical Strike Chance for Spells.

Campaign Buffs

Quest rewards during the campaign offer a selection of buffs to your character. Choose the following buffs for the build:

• Valley of the Titans Altar: 30% increased Charm Charges gained
• Venom Draught: 25% increased Stun Threshold
• Trial of Ngkanu: Resistances
• Goddess of Justice: 20% increased Life Recovery from Flasks
• Seven Pillars: 3% Movement Speed

For more details, check the guide on Campaign Difficulties and Permanent Stat Bonuses.

Flasks and Charms

Prioritize the following Flasks and Charms:

• Health Flask
  • Prefix: Increased Life Recovered, Remove Life Recovered from Mana when used
  • Suffix: Increased Charges
• Mana Flask: not used
• Charms
  1. Thawing Charm: Increased Duration
  2. Stone Charm: Increased Duration
  3. Silver Charm: Increased Duration (The Fall of the Axe Unique Silver Charm preferred)

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Changelog

• December 24th, 2025: Build guide video added.
• December 19th, 2025: Guide created for The Last of the Druids League (Patch 0.4).