Synthesis Guide
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Back to topHow Synthesis Works
Synthesis is the Cube's core upgrade mechanic. The rule is simple:
Items, accessories, and materials all use the same 9:1 rule. The result tier is determined by probability.
Equipment, accessories, and materials can all be synthesized. The result is always a random item of the target tier — you don't get to choose the slot or class. This is the tradeoff: guaranteed rarity upgrade, but random output.
Key insight: The expected sale value of a synthesized item is roughly 1/3 of the total sale value of the 9 items used. When gold is tight, selling items through Alchemy is better than synthesizing them.
Synthesis Success Rates
These rates are derived directly from the game's datamined migration weights. The outcome probabilities determine whether you get +1 tier, +2 tiers (lucky break), or stay at the same tier.
| Input Rarity | +1 Tier | +2 Tiers | Same Tier |
|---|---|---|---|
| Common | Uncommon 95.24% | Rare 4.76% | — |
| Uncommon | Rare 96.15% | Legendary 3.85% | — |
| Rare | Legendary 97.56% | Immortal 2.44% | — |
| Legendary | Immortal 99.01% | Arcane 0.99% | — |
| Immortal | Arcane 49.88% | Beyond 0.25% | 49.88% |
| Arcane | Beyond 33.28% | Celestial 0.17% | 66.56% |
| Beyond | Celestial 23.06% | Divine 0.08% | 76.86% |
| Celestial | Divine 16.66% | Cosmic 0.02% | 83.32% |
| Divine | Cosmic 9.09% | — | 90.91% |
Rates computed from datamined synthesis migration weights. Cosmic tier cannot be synthesized further.
Cube Level Requirements
| Cube Level | Unlocks |
|---|---|
| Lv.1 | Synthesis (Common → Legendary range) |
| Lv.10 | Immortal Synthesis unlocked |
| Lv.50 | Celestial Synthesis unlocked |
You need Cube Lv.10 to synthesize into Immortal, and Cube Lv.50 to reach Celestial and beyond. These are major progression milestones.
Synthesis Strategy
Early Game (Common → Legendary)
- Synthesize aggressively. Rates are 95%+ to upgrade. There's almost no downside.
- Legendary is the minimum rarity for Steam Market trading — pushing items to Legendary unlocks their economic value.
- Save duplicate gear of the same type for synthesis. 9 Rare Swords → 1 Legendary Sword (controlled input = controlled output).
Mid Game (Immortal → Arcane)
- The 50% wall: Half your Immortal syntheses will stay Immortal. This is where gold costs start to matter.
- Before synthesizing, check: is the expected sale value worth more than 9× Alchemy gold? If gold is tight, sell the base items instead.
- Arcane items are the first tier where synthesis becomes genuinely expensive. Stockpile before committing.
Late Game (Beyond → Cosmic)
- Expectation management: At Celestial → Divine, you'll stay same-tier 83% of the time. A single Divine item requires dozens of Celestial synthesis attempts on average.
- Synthesize in bulk batches. The variance is brutal — 10 attempts might all fail, then 2 succeed back-to-back.
- Cosmic is the final tier — Divine → Cosmic has only a 9% success rate. This is the ultimate long-term goal.
The Math
Starting from 9 Common items, here's how many you need on average to reach each higher tier:
| Target Tier | Avg. Common Items Needed | Avg. Synthesis Attempts |
|---|---|---|
| Uncommon | 9 | 1 |
| Rare | ~85 | ~9 |
| Legendary | ~780 | ~87 |
| Immortal | ~7,100 | ~788 |
| Arcane | ~28,000 | ~3,100 |
| Beyond | ~170,000 | ~18,500 |
| Celestial | ~1,400,000 | ~155,000 |
| Divine | ~17,000,000 | ~1,900,000 |
| Cosmic | ~340,000,000 | ~38,000,000 |
Estimates account for "same tier" flowback and +2 tier lucky breaks. Actual numbers vary with RNG.