There are essentially 2 strategies to defeat Iragoth. You can either increase his cooldowns constantly and keep his strongest attacks at bay, or tough it out with extra survivability (Increase DEF, Shields, debuff cleansing, and lots of Healing). In both cases, you need to target down the Eternal Priest whenever he’s up in order to reset your cooldowns and kill the Guards to prevent Iragoth from healing himself, which means you also need to do enough damage and be fast enough to beat Iragoth’s cooldowns on his A3 and P2.
Team composition
My team composition against Iragoth is the following:
Inquisitor Shamael (lead): I use Shamael for his accuracy lead because my strategy is to land the Increase Cooldown from Sinesha. Shamael is also a great damage dealer, helping me kill the Eternal Priest and bring down the dragon.
Lydia the Death Siren: Lydia is risky if Iragoth ever gets to his A3, but if I manage to get Sinesha to land her Increase Cooldown it’s not something I worry about, and I get all of the benefits of having Lydia.
Sinesha: Sinesha is key here to increase Iragoth’s cooldowns, preventing his A3.
Underpriest Brogni: I use Brogni for survivability and for his Block Debuffs.
Doompriest: The ever-useful Doompriest helps with his debuff cleansing and healing.
Here’s an alternate team composition that’s more accessible (no Legendaries and no Void Epic/Legendaries):
Jareg (lead): Jareg is a beast for Iragoth. His entire kit helps keep you alive, with an A1 Decrease ATK, Ally Protection and Increase DEF on the A2, the passive that gives Continuous Heal ever time you get hit for >20% of MAX HP, and the +33% HP Aura.
Apothecary: Great support with Increase SPD and healing.
Vrask: Another great support with very small cooldowns and who heals with every crit.
Geomancer: Great damage dealer you can use to bring the Dragon down the HP Burn and Weaken.
IRAGOTH THE ETERNAL DRAGON SKILLS
A1: Spike Storm. Attacks all enemies. Places a [Block Cooldown Skills] debuff for 1 turn.
A2: Spirit Rush. Attacks all enemies. Inflicts bonus damage for every turn remaining on all enemy skills’ cooldowns (+20% damage for each turn of cooldown). Places a [Fear] debuff on enemies with no skills on cooldown. (cooldown: 3)
A3: Soul Burst. Attacks all enemies. Puts all enemy skills on cooldown. Fills Iragoth’s Turn Meter by 5% for every turn remaining on all enemy skills’ cooldowns. (cooldown: 3) [Note for clarity: this skill adds TM to Iragoth for each turn of cooldown that Soul Burst adds, so having skills that are not on cooldown or have especially long cooldowns will increase the TM received by Iragoth]
Passive 1: Conjure Souls. Summons three minions at the start of the turn: one Eternal Priest then two Eternal Guards. Iragoth can have a maximum of 3 minions in battle at any time. Places an [Eternal Rage] buff on Iragoth for 2 turns if only one Eternal Priest is summoned or no minions are summoned by this skill. This buff cannot be removed or blocked. The [Eternal Rage] buff increases Iragoth’s SPD and causes Iragoth to ignore [Unkillable], [Block Damage], [Shield] buffs and ignore 50% of the target’s DEF when attacking.
Passive 2: Consume Soul. At the start of the turn, sacrifices an Eternal Priest, resets the cooldowns of Iragoth’s skills, and grants an Extra Turn. If there are no Eternal Priests on the team, sacrifices an Eternal Guard and heals Iragoth by 15% of Iragoth’s MAX HP. [This skill will be on a 4-turn cooldown at the start of the battle, and will activate and go on cooldown every 5 turns even if there are no Eternal Priests or Eternal Guards on the team.]
Passive 3: Otherwordly. Immune to [Stun], [Freeze], [Sleep], [Provoke], [Block Cooldown Skills], [Fear], [True Fear], [Decrease SPD], [Poison] and [Heal Reduction] debuffs. Also immune to HP exchange effects, HP balancing effects, and Turn meter reduction effects.
Passive 4: Almighty Strength. Damage from skills that scale based on Enemy MAX HP cannot exceed 10% of Iragoth’s MAX HP.
Eternal Priest skills:
A1: Bolt Strike. Attacks 1 enemy. Places a [Block Cooldown Skills] debuff for 2 turns.
Passive: Unbound Souls. Resets the cooldowns of all enemies’ skills when this Champion is killed by an enemy.
Eternal Guard skills:
A1: Guard Break. Attacks all enemies. Places a 60% [Decrease DEF] debuff for 2 turns. Also places a [Provoke] debuff for 1 turn on enemies under [Block Cooldown Skills] debuffs.
Passive: Eternal Protection. Decreases the damage taken by allies from AoE attacks by 75%.