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PoE 2 Build

Doomcaster Gemling

Mercenary

Gemling Legionnaire

End Game

0.5 RotA

By Definitiv

Updated on Jun 22, 2026

Jun 22, 2026

Build Overview

The Doomcaster Gemling destroys all Content with Impending Doom. A simple One-Button* Playstyle for both Bossing and Mapping. Utilizing several powerful Interactions to boost Damage Numbers to the Extreme. Capable of destroying all Endgame Content, including 200% Delirium.

Combining Advanced Thaumaturgy with Despair and Archmage sets the Skill Cost to 0, but still reaps the full benefits of Mana Stacking from Archmage, which gets an additional 50% stronger from Gemling Quality.

With Despair covering the Entire Screen and having multi-hits built in, there is no need for Cast on Critical or Cast on Elemental Ailment, keeping this build truly simple and reducing the cost and stress on Gear as we only require +15 Spirits on Boots or Amulet Base.

*technically not a true One-Button, as we use Adonia's Ego Pinnacle of Power every Minute once, which is 4 Buttons for 152% more Damage.

Minimum Requirement

Split Personality Ruby(Shadow or Sorceress),
40% Quality on all Skill Gems
- 20% from Gemcutter's Prism
- 6% from Gemling Ascendancy
- 5% from Fox Idol,
- 5% from Paragon Annoint
- 4% from either Gem Quality Desecrate on Amulet or Loreweave

How to Level?

I levelled to Level 90 as Strength Stacker from Level 1 with Facebreaker, replaced at Level 78 by Brutus' Lead Sprinkler. Super smooth and fun. You can find the Full Levelling Guide here.

Build Troubleshooting

Casting Despair drains my Mana
1. You are not at 40% Quality
2. You have allocated Raw Mana
3. You are using Doedre's Undoing instead of Cursed Ground (Toads have Archmage Mana Cost per Proc)
Despair doesn't proc Impending Doom
1. Your Curse Activation Frequency is at or above 100%, lower it to at most 99%
I am constantly out of Mana
1. Make sure Mana Remnants is activated and that you have Empowering Remnants + Remnant Attraction allocated
I am losing life on Despair Cast
1. Make sure to use a cultivated Rathpith Globe, without the Non-Channeling Spells cost an additional 6% of Life
My Damage is low
1. Is your Despair at least at Level 35? Get additional Gem Levels from Gem Corrupt, cultivated The Vertex (skill gems) and Prism of Belief
2. Is your Critical Hit chance near 50%? Get increased Critical Hit Chance from Rathpith Globe and Passive Tree
I can't allocate my Passive Tree like in the Guide.
1. Are you using the correct Split Personality Ruby? Make sure it is either Shadow(recommended) or Sorceress
2. Are you using the correct From Nothing? Make sure it says either Eldritch Battery or Conduit

Strengths and Weaknesses

'One-Button' Playstyle
No Mana Sustain Issues
No Cast On Shenanigans
Screenwide Clear
Boss Nuker
200% Deli Viable
Partially Alternative Gear to Meta

4 Button Buff every ~1 Minute
Requires Several Uniques & specific Modifiers on Rares to get started!
Expensive Min Max Items

Build Variants

Initial Setup {1}

My Setup {2}

Aspirational {3}

A specked down Variant of my Setup, which reduces the Cost while retaining most of the Damage

Equipment

Initial Setup {1}

My Setup {2}

Aspirational {3}

Set 1

Set 2

Equipment Priority

+11

Gear

See Gear Notes or Ingame Build Planner for Detailed Notes

Charms

Rite of Passage is fully optional, but if you have any Vivid(Stag, Cat or Wolf) or a Bear one, feel free to use. Alternative use Beira's Anguish

Nascent Hope and Stone Charm for Defense

Flasks

Ultimate Life Flask with More Recovery on Low Life

Lavianga's Spirits or Uhtred's Chalice

Jewels

Split Personality Ruby (Sorceress or Shadow)
From Nothing (Eldritch Battery or Conduit)
Prism of Belief (Despair, pref +3)
Time-Lost Sapphire
- Very Large
- Notable Curse AoE
- Notable Spell Crit Damage Bonus
- Notable Spell Crit Hit Chance
- [Optional] Notable Crit Hit Chance or 25% more Notable Effect
at Least 1 rare Sapphire
- faster curse Activation (required)
- Spell Critical Hit Chance (craftable with Liquid Despair)
- any combination of Spell Damage, Triggered Damage, Curse AoE, Cast Speed or Crit Damage Bonus

Optional use Voices Sapphire and additional Sapphire or Megalomaniac or Heart of the Well

Megalomaniac Annoints:

Cooked
Dark Entries
Paragon
Mystic Avalanche
Aspiring Genius
Harness the Elements

Heart of the Well Affixes:

Mana on Kill
Spell Critical Hit Chance and/or Critical Hit Chance
Spell Crit Damage Bonus and/or Crit Damage Bonus
Lucky Lightning Damage Chance

Skill Gems

Initial Setup {1}

My Setup {2}

Aspirational {3}

Support Gem Requirements:

Str 50

Dex 50

Int 50

Despair

Level 20

Archmage

Level 18

Mana Remnants

Level 20

Pinnacle of Power

Level 20

Firestorm

Level 18

Frost Bomb

Level 18

Level 20

Power Siphon

Level 18

Power Siphon

Level 19

Pinnacle of Power

Level 20

Tornado

Level 13

Volcano

Level 13

Thunderstorm

Level 13

Gem Priority

+30

Main Skill

Despair in Weapon Set 1 is the Main Skill of the Build. It doesn't do any Damage itself, but Impending Doom supporting Despair does.

Impending Doom mirrors the Gem Level of the Curse it is supporting and will trigger Doom Blast whenever the Curse expires on an afflicted Enemy. That Outcome can be forced early by supporting Despair with Cursed Ground and Spell Cascade. Cursed Ground gives Despair a limit of 2 Cursed Grounds and Spell Cascade causes 3 Cast of Despair, the 3rd one replacing the original Cursed Ground. This causes the Curse on Enemies on top of the Cursed Ground to immediately expire and proc Doom Blast. Spamming Despair will result in additional Damage Procs from the Cascade Casts as it keeps replacing the active Cursed Grounds.

To guarantee this works properly, make sure that:

Curse Application Delay has to be lower than Cast Time. (Can be checked in Tooltip while unsocketing Cursed Ground)
Have at least 4.7, preferred 5.2 Curse Radius for proper Damage overlap.
Use Cursed Ground not Doedre's Undoing. Doedre's works technically, but the Toads consume Mana because of Archmage
40% Quality on Despair and using Advanced Thaumaturgy for 100% reduced Mana Cost.

2 Support Sockets are flexible for Damage Supports:

BiS is Rakiata's Flow, just biggest Damage Boost, get this ASAP
Zenith II is recommended for easy conditional 30% more
Considered Casting is possible, but not recommended due to lower Cast Speed
Deliberation works as filler.
Vorana's Siege works, as a 'semi-budget' option for Rakiata's Flow
Execute III, IF using Archmage with Atziri's Communion.

Notably Impending Doom triggers Doom Blast, which means Dynamism and Invocated Efficiency scales Doom Blast Damage.

Power Up Setup

I recommend using a Adonia's Ego to get access to Pinnacle of Power. With our setup, that is a 152% More Damage, which is better than any Wand, except the best mirror-tier wands.

Only at the highest Budget do I recommend swapping to a Rare Wand, not for the Damage, but for the QoL. To only use 1 Button and not have to worry about keeping the Buff up ever.

Frost Bomb and Powered by Verisium (requires Gloves to be Runeforged) to generate 6 Infusions

Firestorm with Unleash or Zarokh's Refrain(more fancy, but not required) to consume Infusions and generate Power Charges with Infusion of Power

Swap back to WS 1 by using Despair and consuming Power Charges with WS 1 Pinnacle of Power to get 1 Minute of 152% more Damage + ability to Freeze. 20% Chance to be 2 Minutes with Heightened Charges AND 300% more Damage. [No requirement to fish for this, we do enough Damage already]

Notably Pinnacle of Power cannot force a Weapon Set Swap; this has to be done manually by casting Despair

Spirit Skills

Archmage with 40% Quality only reserves 83 Spirit, so only need +13 to fit Mana Remnants too.

Only use Archmage in Weapon Set 1, so when using our Buff Setup, we don't spend unnecessary Mana.

Potential Adjustment to the Build could be to support Archmage with Atziri's Communion to get access to Low Life for Pain Attunement, Execute III and Final Barrage. Quick Pobbing did not feel worth the Investment, but if you have a Communion, give it a go and see how it feels in-game.

Use the freed up Spirit for Remnants of Kalguur and allocate Arcane Remnants or get Blink into the Build for faster Mapping.

Cast on does not work cause our Damage comes from Impending Doom Doom Blast, which is already a triggered Skill and cannot grant Energy.

Filler Skills & Filler Supports

3 Skill Slots are unused. It is recommended to fill them with Pure Int(Occult or Elemental) or Str/Int Hybrid (Primal) Skills to get additional Motes for Virtuous Barrier.

An additional 3 Skill Slots can be used in the same Manner if you replace Adonia's Ego with a Rare Wand, as Firestorm, Frost Bomb and Powered by Verisium become obsolete.

To fully benefit of Gem Studded it is required to balance the Support Gems.

All Supports in Power Siphon and WS 2 Pinnacle of Power are only there to balance for Gem Studded.

Passive Tree

Initial Setup {1}

My Setup {2}

Aspirational {3}

main:

123

set 1:

set 2:

Ascendancy

Essence of Virtue
Advanced Thaumaturgy
Implanted Gems (+2 to Intelligence Gems)
Either
1. [Recommended] Gem Studded
2. Adaptive Capability

Advanced Thaumaturgy is a must and the Core of all our Interactions.

Gem Studded grants Crit Immunity, better QoL as we aren't slowed as much. If only tapping Right Click for Despair, you barely slow down. And Less Cost, which is neat for our Buffing.

Adaptive Capability would yield +35 Intelligence for 70 Base Mana, personally, I like the Crit Immunity way more.

Passive Tree

To allocate the Tree as seen above, path from Mercenary Start to the Top Left Jewel Socket near Mind Over Matter. Socket Split Personality Ruby (Shadow or Sorceress) and then allocate Nodes as seen above from the new Starting Point to the Split Personality. Then respec all unnecessary Travel Nodes from the Mercenary Starting Point and allocate Tree as seen above.

Impending Doom has the Trigger Tag and scales of Trigger Damage. we also already get a lot of Critical Hit Chance and Generic Damage Increase from Rathpith Globe

Mainly focus on Critical Hit Chance and Critical Damage Bonus from Passive Tree.

Mind Over Matter + Eldritch Battery for Easy Defense.

Do not allocate Raw Mana!!!

Use Weapon Set 2 Points for Power Charges and Infusion of Power

From Nothing (Eldritch Battery or Conduit) with a Very Large Range Time-Lost Sapphire in the Socket next to Invocated Efficiency is very powerful for the Build.

Quest Rewards

Check which quests you’ve completed on your character

Clearfell — Beira of the Rotten Pack

+10% to Cold Resistance

Hunting Grounds — The Crowbell

Grants Two Weapon Set Passive Skill Points

Freythorn — The King in the Mists

+30 to Spirit

Ogham Farmlands — Una's Hut

Grants Two Weapon Set Passive Skill Points

Ogham Manor — Candlemass, the Living Rite

+20 to maximum Life

Keth — Kabala, Constrictor Queen

Grants Two Weapon Set Passive Skill Points

Valley of the Titans — Medallion

30% increased Charm Charges gained

+1 Charm Slot

Deshar — Final Letter

Grants Two Weapon Set Passive Skill Points

The Spires of Deshar — Sisters of Garukhan

+10% to Lightning Resistance

Jungle Ruins — Mighty Silverfist

Grants Two Weapon Set Passive Skill Points

The Venom Crypts — Venom Draught

25% increased Stun Threshold

Jiquani's Machinarium — Blackjaw, the Remnant

+10% to Fire Resistance

The Azak Bog — Ignagduk, the Bog Witch

+30 to Spirit

The Molten Vault — The Molten Vault

Reforging Bench

Aggorat — Blood Sacrifice

Grants Two Weapon Set Passive Skill Points

Journey's End — Captain Hartlin

Two Weapon Set Passive Skill Points

Skill Gem(Lv 13)

Delirium Drop

Eye of Hinekora — Navali's Rest

5% increased Maximum Mana

Halls of the Dead — Yama The White

Grants Two Weapon Set Passive Skill Points

Halls of the Dead — Tawhoa's Test

+5% to Lightning Resistance

Abandoned Prison — Goddess of Justice

30% increased Life Recovery from Flasks

Halls of the Dead — Tasalio's Test

+5% to Cold Resistance

Halls of the Dead — Ngamahu's Test

+5% to Fire Resistance

Halls of the Dead — Tribal Medicine

30% increased Armour, Evasion and Energy Shield

Wolvenhold — Oswin, the Dread Warden

Grants Two Weapon Set Passive Skill Points

The Khari Crossing — Akthi and Anundr

Two Weapon Set Passive Skill Points

The Khari Crossing — Molten Shrine

5% increased Maximum Life

Qimah — Tabana's Pillar

+5 to all Attributes

Kriar Village — Lythara, the Wayward Spear

+40 to Spirit

Howling Caves — The Abominable Yeti

Grants Two Weapon Set Passive Skill Points

How it Plays

At the start of the map, and then every ~50 Seconds (120 if Heightened Charges procs) or before Entering a Boss Room/ during Boss Starting-Animation

Use Frost Bomb, Powered by Verisium, then Firestorm -> Despair + WS 1 Pinnacle of Power. This takes like 2 Seconds once used to the Rotation

Cast Despair, tap for Mapping, and hold down on Bosses for max Damage output.

Collect Mana Remnants to Overflow Mana for better Max Hit Pool or when getting hit to recover Mana faster.

How it Works

Impending Doom mimicks Despair Level and Support Gems.
- Procs on Curse End, which can be forced instantly with Cursed Ground and Spell Cascade, casting 3 Curses with a Limit of 2. The Main Cast always gets replaced.
- Subsequent Cast also replaces the 2 previous Grounds, resulting in up to 2 Additional Hits on Large Enemies
- Impending Doom has a Base Cooldown of 0.15 Seconds, with 6 Uses, as long as Cast Time is above 0.15, we never run out of Uses.
Advanced Thaumaturgy + Despair reduces Casting Cost to 0 Mana even with Archmage
- Level 38-40 Despair for innate Flat Damage on Impending Doom
Advanced Thaumaturgy + Archmage for an additional 2% Damage as Extra per Mana
- At 3,5k Mana, that is 210% Damage as Extra Lightning total
- requires only 13 Spirit from Boots with 40% Quality to fit Archmage + Mana Remnants,
  NO Atziri's Communion required.
152% more Elemental Damage from Pinnacle of Power (Adonia's Ego)
- *technically not a One-Button Build, 4 Button Presses every ~1 Minute or before entering Boss Rooms, but better Damage than Mirror Tier Wand
- access to Freeze
- 20% chance for 300% More Damage with Heightened Charges
- Frost Bomb + Powered by Verisium to generate Infusions and consume with Firestorm and Infusion of Power to generate Power Charges for Adonia's Ego only on Demand, bypassing the Downside.
Eldritch Battery + Mind Over Matter + Mana Remnants for easy Sustainable additional Defense
- + Damage as Extra scaling with Archmage
- + %Damage & Crit Chance scaling from Rathpith Globe
- Total Hit Pool of ~7.5-9k with Mana Overflow based on Budget/Gear
From Nothing (Eldritch Battery or Conduit) + Very Large Time-Lost Sapphire for efficient Passive Point allocation