Mosaic Assassin Build Guide
By the DiabloBytes team · Updated March 2026
⚠️ Ladder Removal Warning
The Mosaic runeword was removed from Ladder play in the Reign of the Warlock patch (Season 13 / Patch 3.0). It still functions fully in Non-Ladder (offline and online Non-Ladder). Do not expect this build on a fresh Ladder season.
The Mosaic Assassin — also known as the Phoenix Strike Assassin or "PS Sin" — is the undisputed queen of Assassin builds. She wields the Mosaic runeword (Mal + Gul + Amn in a Claw) in both hands, which grants a 100% chance to not consume charges from charge-up skills when using a finishing move, while simultaneously refreshing their timers. The result: perpetual max-charge uptime on every charge-up skill you equip.
The core offensive engine is Phoenix Strike for Fire, Lightning, and Cold charges, plus Claws of Thunder and Blades of Ice as additional charge-up skills. Dragon Talon is the primary finishing move — it releases all stacked charges in a devastating multi-kick AoE that wipes entire screens. Nothing resists your full damage output because you hit three elements simultaneously.
The build is extremely tanky thanks to Fade, Weapon Block, and Cobra Strike's life leech on charges. Gear investment is significant — dual Mosaics require endgame runes — but the payoff is a build that trivializes virtually every area including Ubers. You can also pass for a Christmas tree in combat, which is a bonus.
Skill Allocation
Put 1 point into each support skill, then max the offensive skills in order:
Primary charge-up skill and the heart of the build. Charge 1 drops a Fiery Meteor (Fire), Charge 2 delivers Chain Lightning (Lightning), Charge 3 triggers a circular Freezing Nova (Cold). Each element is a separate damage type — nothing is immune to all three.
Primary finishing move. Executes rapid multi-hit kicks that release all stacked charges without consuming them (Mosaic). Each kick fires the charges, so more Dragon Talon kicks = catastrophic damage in a massive AoE.
Second charge-up skill. Charge 1 adds Lightning Damage, Charge 2 is a Lightning Nova AoE, Charge 3 releases Charged Bolts in all directions. Stacks alongside Phoenix Strike for a double layer of Lightning AoE.
Physical charge-up. Massively amplifies the Physical Damage component of Dragon Talon. Max for synergy and raw damage boost on the kick itself before the elemental charges detonate.
Third charge-up for Cold. Charge 3 releases a large AoE Cold Explosion that Freezes enemies. Adds another full Cold layer on top of Phoenix Strike's Cold charge. Remaining skill points go here after core skills.
Grants massive All Resistances, Physical Damage Reduction, and Curse Duration Reduction. Each soft point (from +skills gear) adds 1% PDR. Keep active at all times — buff before entering any dangerous area.
Free block chance while dual-wielding claws. Even 1-2 hard points grants solid passive blocking scaled by your +skills gear. Invest remaining points here after maxing core offensive skills.
Cloak of Shadows blinds ranged enemies and drops their Defense. Mind Blast stuns and converts. Dragon Flight teleports you to a target and kicks — excellent mobility before Enigma. Shadow Warrior provides a meat shield.
Stat Points
Enough to wear gear only — typically 156 for most endgame claw bases. Use charms and gear bonuses to reach the requirement wherever possible.
Enough to equip gear. Dual-claw Weapon Block does not require Dex investment to reach high block percentages — the skill itself handles it. Keep this minimal.
Everything else. You want 3,000+ HP in Hell. You're constantly in melee range — Cobra Strike's life leech helps sustain, but HP is your safety net when surrounded.
None. Zero. Cobra Strike's mana leech charges handle sustain completely. Don't waste a single point here.
Gear
Dual Mosaic claws are the build. Everything else amplifies them.
Required: Mosaic (Mal+Gul+Amn) in both hands — this IS the build. Must be in a claw-type weapon.
BiS: Mosaic in a high-roll Scissors Suwayyah or Runic Talon with +2 Martial Arts / +3 Phoenix Strike mods rolled on the base before socketing.
Budget: Harlequin Crest (Shako) socketed with Um for +2 skills, life/mana, and resistances.
BiS: Griffon's Eye with a 15% IAS jewel for massive Lightning Damage boost and FCR.
Budget: Treachery (Shael+Thul+Lem) for 45% IAS and Fade proc.
BiS: Enigma in a Mage Plate for Teleport mobility and +2 skills.
Budget/BiS: Dracul's Grasp for 25% chance to cast Life Tap (invaluable against tanky bosses and Ubers) and life leech. Or Laying of Hands for IAS and +350% Demon damage.
Budget/BiS: Verdungo's Hearty Cord for +10-15 Vitality and 10-15% Damage Reduction. The DR stacks excellently with Fade's PDR.
Budget: Rare boots with FRW and resistances.
BiS: Upgraded Gore Rider for massive Kick Damage bonus, Crushing Blow, and Deadly Strike — all apply to the Dragon Talon physical hit.
Rings: Ravenfrost (Cannot Be Frozen) + rare ring with life leech and resistances, or dual Bul-Kathos Wedding Band for +1 skills and life leech.
Amulet: Mara's Kaleidoscope for +2 skills and all resistances, or +2 Assassin amulet with life/res.
Call to Arms + Spirit Monarch for Battle Orders / Battle Command pre-buff. After buffing, swap back to dual Mosaics.
Mercenary
Act 2 Nightmare Offensive (Might Aura) — The Might aura amplifies your Physical Damage component on Dragon Talon, which feeds into the fire explosion size. For endgame, equip with Infinity in a Thresher for Conviction aura to pierce resistances and break some immunities. Pair with Fortitude armor and Andariel's Visage with a Ruby Jewel of Fervor for max damage and survivability.
Playstyle Tips
- Pre-buff with Weapon Swap: cast Battle Command (twice) then Battle Orders from Call to Arms, then swap back to dual Mosaics.
- Build charges by hitting enemies with Phoenix Strike, Claws of Thunder, and Blades of Ice — stack all three to max charges before using Dragon Talon.
- After the initial charge-up, you only need to hit a target once every 15 seconds to keep all charges refreshed (Mosaic handles the rest).
- Dragon Talon is your primary finisher — it kicks rapidly, releases all charges each kick, and never consumes them. More points = more kicks = more detonations.
- Use Dragon Flight to jump into packs before getting Enigma — it teleports you directly to a target and kicks, counting as a finisher to maintain charges.
- Cast Cloak of Shadows against ranged-heavy areas to blind enemies and drop their defense. Use Mind Blast to stun/convert anything that gets too close.
- For Diablo: convert a monster via Mind Blast before opening the last seal to maintain your charges through the spawn delay.
- This build doesn't have immunity problems — Phoenix Strike's three damage types ensure something always hits. Use whichever charge element the enemy is weakest against.
Leveling Progression
Mosaic is an endgame runeword — level with traps until you can equip it. Respec only once you have both Mosaic claws in hand.
Highlight Mosaic Assassin Drops
Highlight Claw bases for Mosaic (Scissors Suwayyah, Runic Talon), Mal + Gul + Amn runes, +Martial Arts claws, and Gore Rider boots.
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