Hero Siege Cthulhu drops

Location & trigger

Cthulhu is the Act 9 boss. Defeat Cthulhu on Inferno for Cthulhu’s Soulgem. The tablet-summoned encounters in Shipwreck Cove, Tormented Reef and Boreal Island are different boss fights.

Entry materials & uses

Tablet of Armada summons Captain Grimtide, Tablet of Parasite summons Blood Maiden, and Tablet of Leviathan summons Phantom Leviathan. Use those tablets for their respective fights, not for Cthulhu’s Soulgem. Cthulhu’s Soulgem is a socketable Gem with a required character level of 90.

Compare encounters

Choose Cthulhu for the all-resistance Soulgem, Corrupted Odin for the cold-focused Soulgem, or Mevius for the arcane-focused Soulgem. Each Soulgem comes from its corresponding boss on Inferno. Keep the gem’s level requirement separate from the difficulty used for the fight.

Reward uses & preparation

Cthulhu’s Soulgem grants +8% to All Resistances and -5% to All Enemy Resistances. Odin’s Soulgem grants 5% increased Cold Skill Damage, -5% to Enemy Cold Resistance and +10% to Cold Resistance. Mevius’ Soulgem grants 5% increased Arcane Skill Damage, -5% to Enemy Arcane Resistance and +10% to Arcane Resistance. Compare the damage element of your build before choosing a Soulgem: the all-resistance bonuses serve a different purpose from a single-element damage bonus.

Difficulty & item conditions

Cthulhu's Soulgem has an Inferno condition. All named rewards on this page carry that condition. The item’s required character level is an equipment requirement, not a minimum area level.

Related sources