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Ball Lightning/Arc Mjölner CoC Assassin Build

Ball Lightning/Arc Mjölner CoC Assassin Build

Extremely fast Map farming build based on the Legendary Mjölner Unique Mace

Ball Lightning/Arc
Assassin build

Updated for Patch 3.9

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Guide notes
January 19, 2020
-Build created
January 20, 2020
-Added gameplay video


Mjölner is a legendary Mace which has one of the most efficient trigger mechanics in Path of Exile. Whenever you hit enemies, it will trigger socketed Lightning Spells with greatly increased damage and additional Chain. Combining it with Cast on Critical Strike Support setup as an Assassin (who makes it easiest to reach nearly 100% effective Chance to Crit) lets you unleash a destructive force to be reckoned with. Mjölner will cast Arc, while CoC will trigger Ball Lightning Spell. These two spells combined offer insane clearing and very high single-target DPS.

On the other hand, this build utilizes Chaos Inoculation Passive making it reliant on Energy Shield and Energy Shield Leech. The only "downside" to this build, is Mjölner's high attribute requirement, requiring you to stack over 400 Strength. This is not that hard if you are above level 80, but makes it pretty much impossible to be used effectively on lower levels. You most likely aren't doing this character as your first one, so in this guide, we will assume that you have some spare Chaos that you can invest in leveling gear like Poet's Pen and respec at around level 80 from Life to full Energy Shield. At this point, you should have all the gear prepared. 

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1. Gameplay

This Mjölner Arc/Ball Lightning Assassin is a "spin to win" type of character. All you need to do is to spam Cyclone to trigger massive amounts of Lightning Spells (Arc and Ball Lightning in this case) obliterating enemies all over your screen. In terms of playstyle, it's very similar to our Cospri's Ice Nova Assassin but based on Lightning Elemental Damage and different Items. This build is also quite tanky, with over 8,000 Energy Shield, Elusive buff, and high Energy Shield Leech. 

0:07 Tier 13 Plateau with Al-Hezmin Stronghold
0:55 Tier 14 Residence
1:19 Tier 15 Coral Ruins
1:29 Tier 15 Courtyard
1:46 Tier 15 Park

This video was recorded on a level 92 Assassin on Standard. We pushed this build easily to Sirius 4 on a 12 Exalted Orbs budget - while the clear speed and overall farming experience was second to none

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2. Build's PROS & CONS

  • one of the fastest builds we have played
  • amazing mobility and clear speed
  • solid defenses based on Energy Shield and Energy Shield Leech
  • very high single-target DPS
  • requires stacking attributes for mandatory Items
  • you need to level up with different items and skills


3. Leveling tips

Leveling is nearly impossible as Energy Shield-based character, and as you want to switch to Mjölner, you will need a lot of Items with all the Attributes required for it prepared beforehand. Because of that, we will assume that it's not going to be your first character, and you will be able to get Poet's Pen for the leveling phase, and you will have the required Items when you hit level 80 or so. You can still level up with Poet's Pen up to around 85~ but it's going to be relatively slow. Our recommended leveling Skill Trees are for Poet's Pen/Life character, and we have switched to Energy Shield at level 80 (it's up to you at this point if you want to keep leveling with Poet's Pen or if you will rather want to switch to Mjölner).

Suggested leveling Gem setups:

Power Siphon setup
Power Siphon Power Siphon - it's used as your primary Attack that will trigger Spells socketed in Poet's Pen
Faster Attacks Faster Attacks Support - increases Attack Speed and the rate at which you can trigger the Poet's Pen's Spells
Innervate Support Innervate Support - adds additional Lightning Damage and the Innervate buff when killing enemies. You can use Added Lightning Damage Support instead of it, but Innervate is used in the final build so it's good to level it up
Elemental Damage with Attacks Support Elemental Damage with Attacks Support - increases Elemental Damage with Attack Skills that are supported by it
Arc setup
(Poet's Pen)
Arc Arc - one of the main Spells used in this build. It fires a Chaining bolt of Lightning that damages multiple enemies and offers great clear speed
Added Lightning Damage Support Added Lightning Damage Support
Elemental Focus Elemental Focus Support - greatly increases Arc's Elemental Damage, but makes it unable to Shock
Ball Lightning setup
(Poet's Pen)
Ball Lightning Ball Lightning - the primary source of DPS in this build. It fires a slow Lightning Ball that periodically hits enemies with Lightning
Added Lightning Damage Support Added Lightning Damage Support
Increased Critical Strike Support Increased Critical Strike Support - increases Crit. Chance of Ball Lightning
Utility Gems
Precision Precision - great Aura Spell which increases your Accuracy Rating and Critical Strike Chance
Herald of Thunder Herald of Thunder - grants added Lightning Damage to your Attacks and Spells
Herald of Ice Herald of Ice - grants additional Cold Damage and causes Icy Explosions that shatter whole packs of monsters
Flame Dash Flame Dash - the mobility skill used in this build


We recommend helping Alira for extra Crit. Multiplier and Elemental Resistances

Leveling Skill Trees:

34 Points Skill Tree
Priorities: 1) Coordination 2) Assassination 3) Crackling Speed 4) Throatseeker 5) Cruel Preparation

61 Points Skill Tree
Priorities: 1) Quick Recovery 2) Light of Divinity 3) Devotion

103 Points Skill Tree (level 80 - the moment of respecc to Energy Shield)
Priorities: 1) Heart of Thunder 2) Purity of Flash 3) Arcane Potency 4) Doom Cast

103 Points Skill Tree (level 80 - after switching to Energy Shield)

Recommended leveling items:

Poet's PenPoet's Pen - leveling with Poet's Pen is extremely fast. On lower levels, you can easily progress with just one of those, but farming low-tier Maps before switching to Mjolner may be faster with two
(11-15)% increased Spell Damage
+1 to Level of Socketed Active Skill Gems per 25 Player Levels
Trigger a Socketed Spell when you Attack with this Weapon
Adds 3 to 5 Physical Damage to Attacks with this Weapon per 3 Player Levels
(8-12)% increased Attack Speed
Karui ChargeKarui Charge - amazing amulet, that increases Attack and Movement Speed. The Projectile Damage buff applies to your Ball Lightning as well
+(20-30) to Dexterity
+(20-30) to Strength
(5-10)% increased Attack Speed
+100 to Accuracy Rating
30% increased Projectile Speed
10% increased Movement Speed
30% increased Projectile Damage
GoldrimGoldrim - amazing leveling Helmet which grants very high Elemental Resistances bonus, sufficient for most of the leveling part
+(30-50) to Evasion Rating
10% increased Rarity of Items found
+(30-40)% to all Elemental Resistances
Reflects 4 Physical Damage to Melee Attackers
Level Requirement reduced by 100 (Hidden)
DreamfragmentsDream Fragments - helps with Mana Management and grants Freeze/Chill immunity
+(20-30)% to Cold Resistance
20% increased maximum Mana
50% increased Mana Regeneration Rate
+(30-40)% to Cold Resistance
Cannot be Chilled
Cannot be Frozen


4. Final Skill tree, Ascendancy Points, and Pantheon

Final Skill Tree:

114 Points Skill Tree
114 Points Path of Building (PoB) link

Ascendancy points:

Preferably in that order:

  1. Opportunistic
  2. Mistwalker
  3. Unstable Infusion
  4. Deadly Infusion


Major God: Soul of Solaris 6% Physical Damage Reduction if there is only one nearby Enemy; 20% chance to take 50% less Area Damage from Hits

Minor God: Soul of Garukhan +5% chance to Evade Attacks if you've taken a Savage Hit recently


5. Final Gems links

[DPS] Cyclone/Ball Lightning
(Body Armour)
Cyclone Cyclone - this is our main Attack which will trigger your core Spells - Arc and Ball Lightning
Cast on Critical Strike Support Cast on Critical Strike Support - the most important Gem in this setup. It will cast Ball Lightning on Critical Strikes dealt by Cyclone
Ball Lightning Ball Lightning - your primary source of DPS in this build. It fires a slow-moving projectile that zaps nearby enemies with Lightning Damage
Elemental Focus Support Elemental Focus Support - grants high bonus Elemental Damage but makes Ball Lightning unable to inflict Ailments
Increased Critical Strikes Support Increased Critical Strikes Support - increases your Cyclone's and Ball Lightning's Chance to Critically Strike
Slower Projectiles Support Slower Projectiles Support - reduces Ball Lightning's projectile speed, increasing the number of hits it can land on your enemies
[DPS] Arc
arc Arc - a chaining Lightning Spell which is great for clearing packs and picking out lonely distant targets
Innervate Support Innervate Support - grants added Lightning Damage to your Arc, and when you land a killing blow with it, you will gain the Innervate buff
Culling Strike Support Culling Strike Support - makes Arc instantly kill enemies below 10% Life
[UTILITY] Flame Dash
Flame Dash Flame Dash - increases your mobility
Faster Casting Faster Casting Support
Portal Portal - a very convenient Spell to have. It's totally optional, but since you have an open Socket why not use it
[AURAS] Recommended Auras
Zealotry Zealotry - increases your Spell Damage and Spell Critical Strike Chance
Vaal Discipline Vaal Discipline - grants high bonus Maximum Energy Shield. The Vaal part of this Spell also makes ES Regeneration to be unaffected by incoming damage
Precision Support Precision - increases your Accuracy Rating and Critical Strike Chance. It's extremely important in this build as it defines the rate at which you trigger all your Spells
Enlighten Support Enlighten Support - reduces the amount of Mana Reserved by Supported Spells
[UTILITY] Immortal Call
Cast when Damage Taken Support Cast when Damage Taken Support - will auto-cast Immortal Call after a certain amount of damage is taken. Keep this Gem at level 1
Immortal Call Immortal Call - grants brief Physical Damage immunity. Keep this Gem at level 1
Wave of Conviction Wave of Conviction - applies Lightning Exposure to enemies hit, reducing their Lightning Resistance by 25%. Keep this Gem at level 7 to make CwDT Trigger it as well
Summon Ice Golem Summon Ice Golem - while active, it will increase your Accuracy Rating and Critical Strike Chance. Keep this Gem at level 3
[UTILITY] Vortex
Vortex Vortex - it can be cast instantly while your are spinning with Cyclone. It's used to apply your linked Curse and gain the Arcane Surge buff
Curse on Hit Support Curse on Hit Support - will make Vortex apply your linked Curse when you cast it
Conductivity Conductivity - the recommended Curse for this build. It increases your Lightning Damage output
Arcane Surge Support Arcane Surge Support - keep this Gem at level 5 so that all casts of Vortex will grant you the Arcane Surge buff for extra Spell Damage and Mana Regeneration

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5. Gear Setup

Below you will find all the recommended and required items for this build. It is a rather expensive build without much diversity in terms of Item choices, as you simply have to reach over 400 Strength to equip Mjölner. We may eventually add alternative Item choices in the future, but for the time being we will only include the optimal equipment.

At this point, we would love to invite you to visit our Path of Exile Marketplace where you can buy cheap PoE Currency in case you are unable to complete your build.

Our recommended items will:

  1. Cap your resistances 
  2. Give you enough DPS/Life to start mapping successfully

Stat priorities on items:

  1. Life
  2. Elemental Resistances
  3. Strength
  4. Critical Strike Multiplier
  5. Critical Strike Chance
  6. Accuracy Rating
Rare Helmet(Helmet) Rare Helmet - just pick a rare piece with high base Energy Shield and some Resistances. You should also have an open Suffix that will let you craft up to 30 Strength on it
Min. requirements:
250 Energy Shield
30 Strength (Crafted)
300 Accuracy Rating
Optional affixes:
Elemental Resistances
Nearby enemies have -#% to Lightning Resistance
Helmet enchantments:
Ball Lightning fires an additional Projectile
Mjölner(Weapon) Mjölner - build-defining weapon. It is used to trigger Arc with greatly increased frequency and nearly no Mana Cost. A corrupted one with Fortify chance on Hit will  be the BiS
15% reduced Enemy Stun Threshold
Trigger a Socketed Lightning Spell on Hit
Socketed Lightning Spells deal 100% increased Spell Damage if Triggered
(80-120)% increased Physical Damage
Skills Chain +1 times
+300 Intelligence Requirement
+200 Strength Requirement
(30-40)% increased Lightning Damage with Attack Skills
Rare Shield(Shield) Rare ES Shield - Rare Shield is the only viable option since there are no Unique Ones that will offer Strength attribute
Min. requirements:
220 Energy Shield
30 Strength (Crafted)
50% Spell/Lightning Damage
90% Critical Strike Chance with Spells
Optional affixes:
Elemental Resistances
Rare Body Armour(Body Armour) Rare ES Armor - aim for the highest possible base Energy Shield and some Elemental Resistances
Min. requirements:
500 Energy Shield
75% Total Elemental Resistances
Optional affixes:
Loreweave(Body Armour) Loreweave - this would also work, but it will offer much lower defensive utility when compared to a Rare one
Has 6 Sockets
+(8-24) to all Attributes
Adds (4-10) to (14-36) Physical Damage to Attacks
(20-60)% increased Global Critical Strike Chance
+(15-50) to maximum Energy Shield
+(20-60) to maximum Life
+(20-50) to maximum Mana
(6-30)% increased Rarity of Items found
(15-50)% increased Elemental Damage
Your Maximum Resistances are (76-78)%
Boots(Boots) Rare Boots - again, stack Energy Shield, Movement Speed, and possibly Elemental Resistances
Min. requirements:
100 Energy Shield
60% Total Elemental Resistances
30% Increased Movement Speed
Optional affixes:
Cannot be Frozen (Crafted)
Strength (Crafted)
Boot enchantment:
Damage Penetrates 10% of Enemy Elemental Resistances if you haven't Killed Recently
Adds 1 to 160 Lightning Damage if you haven't Killed Recently
Stygian Vise(Belt) Rare Belt - you can use Stygian Vise for Abyssal Socket, or Crystal Belt for much higher Energy Shield bonuses
Min. requirements:
40 maximum Energy Shield
45 Strength
60% Total Elemental Resistances
Optional affixes:
Elemental/Lightning/Generic Damage increased
Rare Amulet(Amulet) Rare Amulet - pretty much a must-have since it should provide around 50-60 bonus Strength
Min. requirements:
60 Strength
30 Dexterity
25% Critical Strike Multiplier
20% Increased Maximum Energy Shield
Optional affixes:
Elemental Resistances
Recommended Anointments:
  • Whispers of Doom (you can use Elemental Weakness Glove Corruption then)
  • Tranquility
  • Crackling Speed
Rare Ring(Ring) Rare Rings - use two Rares if you are having hard times getting all the necessary attributes, or use one Elder Ring with Mark of the Shaper in your other slot 

Min. requirements:
35 maximum Energy Shield
75% Total Elemental Resistances
Attributes (Strength/Dexterity)
Optional affixes:
Spell/Elemental/Lightning Damage

Mark of the Shaper(Ring) Mark of the Shaper - this Unique Ring grants insane Spell Damage bonus assuming your other Ring is an Elder Item
(15-25)% increased Elemental Damage
20% chance to Trigger Level 20 Summon Volatile Anomaly on Kill
Adds (13-18) to (50-56) Lightning Damage to Spells
(6-10)% increased maximum Energy Shield
(6-10)% increased maximum Life
(60-80)% increased Spell Damage if your other Ring is an Elder Item
Cannot be Stunned by Spells if your other Ring is a Shaper Item
Shaper's Touch(Gloves) Shaper's Touch - since we need to stack a lot of Strength and Intelligence, this is a perfect pick for this build. You can also try getting a pair with some decent Corruption like Elemental Weakness Curse or increased Spell Crit. Chance
(80-120)% increased Armour and Energy Shield
+4 Accuracy Rating per 2 Intelligence
+1 Life per 4 Dexterity
+2 Mana per 4 Strength
2% increased Energy Shield per 10 Strength
2% increased Evasion Rating per 10 Intelligence
2% increased Melee Physical Damage per 10 Dexterity
Militant Faith(Jewels) Militant Faith (Dominus) - we are aiming to turn Minion Instability into Inner Conviction Passive which will grant 3% More Spell Damage per Power Charge (so in this case, 21% more Spell Damage)
Carved to glorify (2000-10000) new faithful converted by High Templar Dominus
Passives in radius are Conquered by the Templars
<two random mods of devotion>
Inertia(Jewels) Inertia - it may be required to reach the Strength needed to equip Mjölner. Socketed it to the left of Chaos Inoculation where it is in range of the +30 Dexterity Node
+(16-24) to Strength
Dexterity from Passives in Radius is Transformed to Strength
Cobalt Jewel(Jewels) Rare Jewels - basically you want maximum Energy Shield on all the Jewels, and it heavily depends on your other equipment whether you will need Resistances, Attributes here, or if you can simply get some extra Spell Damage or Crit. Multiplier
Recommended affixes:
increased maximum Energy Shield
Optional affixes:
Elemental Resistances
Spell Damage/Spell Damage while holding a Shield
Critical Strike Multiplier
Abyss Jewel(Jewels) Abyss Jewels - same as above. You can also try to get one with the chance to Hinder on Spell Hits
Recommended affixes:
maximum Energy Shield
increased Critical Strike Multiplier
Optional affixes:
Chance to Hinder enemies on Spell Hits
Elemental Resistances
Atziri's Promise(Flask) Atziri's Promise - grants very high bonus DPS and Life Leech which comes in handy during Boss fights
+35% to Chaos Resistance
2% of Chaos Damage Leeched as Life during Flask effect
Gain (15-20)% of Physical Damage as Extra Chaos Damage during effect
Gain (10-15)% of Elemental Damage as Extra Chaos Damage during effect
Bottled Faith(Flask) Bottled Faith - grants very high bonus Crit. Chance and damage
40% increased Damage
Creates Consecrated Ground on Use
(30-50)% increased Duration
Consecrated Ground created by this Flask has Tripled Radius
+(1-2)% to Critical Strike Chance against Enemies on Consecrated Ground during Effect
Consecrated Ground created during Effect applies (7-10)% increased Damage taken to Enemies
Other suggested Flasks:
  1. Experimenter's Diamond Flask of Warding (Curse Immunity)
  2. Experimenter's Silver Flask of Heat (Freeze Immunity)
  3. Ample Quicksilver Flask of Staunching (Bleeding Immunity)
Atziri's PromiseBottled FaithDiamond FlaskSilver FlaskQuicksilver Flask

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