Primary Calamity Fragment Explained: A Deep Dive

Primary Calamity Fragments represent a pinnacle-tier key item in Path of Exile 2, introduced in Patch 0.3.0c to gate the game's most challenging boss encounter: the Uber Arbiter of Ash.

Origin and Acquisition

These fragments drop exclusively from Citadel bosses—Geonor in the Iron Citadel, Jamanra in the Copper Citadel, and Doryani in the Stone Citadel—when fought at maximum difficulty with enhanced modifiers. Players must allocate at least 10 points in the Atlas boss tree (any combination works) for Crisis Fragments to upgrade into Primary, Secondary, and Tertiary Calamity Fragments, replacing standard drops. Waystone stacking for higher drop rates from these Citadels is essential, as fragments remain single-use and instance-bound.

Activating the Uber Encounter

Combine the full set of Primary, Secondary, and Tertiary Calamity Fragments at the Burning Monolith on the Atlas (always near the origin) to spawn the Uber Arbiter of Ash portal. This fight features escalated mechanics across two phases: bullet hell patterns, flameblasts, seed explosions in Phase 1, and sword slams, beams, chasms in Phase 2, with a pre-damage claw fireball opener. Death during the Uber version downgrades the instance to the standard Arbiter, preserving fragments for a retry attempt.

Rewards and Loot Potential

Uber Arbiter drops high-end uniques suspected of loot biasing toward rarities, including Solus Ipse Grand Visage (mana/light boosts), Morior Invictus Grand Regalia (defenses/runes), Sine Aequo Grand Manchettes (skill speed), Ab Aeterno Grand Cuisses (movement/dodge), and Sacred Flame Shrine Sceptre (Fire aura buffs). The Prism of Belief Diamond jewel offers corrupted skill level gains, making this the top chase for endgame power spikes.

Strategic Considerations

Atlas progression unlocks boss tree points progressively: initial pairs from high-level map bosses (Tier 15+ waystones at level 79-80+), then Anomalies, Citadels, and finally the Arbiter itself for points 9-10. Stack waystone modifiers and precursor tablets for viability, as Citadel fights demand optimized builds to secure fragments reliably. This system enforces risk-reward, positioning Calamity Fragments as the ultimate progression currency for PoE2's pinnacle content.