The Babylon Key is a Mythical-rarity craftable item in Sailor Piece that exists for a single, high-impact purpose: permanently unlocking the F move on the King of Heroes (Gilgamesh) fighting style. Using it also grants a flat +30% damage buff to your entire build. It cannot drop from enemies, bosses, or chests — the only way to get one is to craft it at a specific NPC on Boss Island after gathering a set of rare materials and equipping the correct race.
Quick answer: Equip the Servant Race, collect 100 Broken Swords, 5 Golden Essence, and 2 Phantasm Cores, then interact with the Babylon Key Crafter NPC on Boss Island to craft the key. Use it from your inventory to unlock the F move and the +30% damage buff.
Babylon Key Crafting Requirements
| Requirement | Details |
|---|---|
| Servant Race | Must be equipped before crafting. Mythical-tier race obtained through race rerolls. |
| 100× Broken Sword | Rare drop from Slime Warriors on Slime Island. |
| 5× Golden Essence | Dropped by the King of Heroes (Gilgamesh) boss. 1.5–2.5% drop chance per kill. |
| 2× Phantasm Core | Dropped by the King of Heroes (Gilgamesh) boss. 0.5–0.75% drop chance per kill. |
The Servant Race is the prerequisite that trips up most players. Because it sits in the Mythical tier, you may burn through many race rerolls before landing on it. Redeeming active Sailor Piece codes is the fastest way to stockpile free rerolls without spending currency.
Where to Find the Babylon Key Crafter NPC
Step 1: Teleport to Boss Island using the portal.
Step 2: Head to the left side of the island and climb to the top of the left palm tree (or large rock area). The Babylon Key Crafter NPC stands there, next to the Divine Grail Crafter.
Step 3: With the Servant Race equipped and all materials in your inventory, press and hold the E key near the NPC. The Babylon Key will appear in the "Items" section of your inventory once the materials are submitted.
Farming Broken Swords Efficiently
Broken Swords are the highest-quantity material you need, but they're also the most straightforward to farm. Travel to Slime Island and defeat Slime Warriors repeatedly. Using a strong sword, a powerful devil fruit, and an upgraded fighting style speeds up clear times significantly. Because you need 100 of them, expect to spend a dedicated session here — but the drop rate is far more forgiving than the boss materials.
Farming Golden Essence and Phantasm Cores from the King of Heroes Boss
Golden Essence and Phantasm Cores are the real bottleneck. Both drop exclusively from the King of Heroes (Gilgamesh) boss, and the odds are punishing. At a 1.5–2.5% chance for Golden Essence and 0.5–0.75% for Phantasm Cores, you'll likely need dozens of kills to collect all seven items.
Summoning the Gilgamesh boss on Normal difficulty costs 1 Divine Grail, 500,000 Money, and 500 Gems per attempt. That cost adds up fast, so stockpile a large supply of Divine Grails before you start your farming run. Running out mid-session and having to pause for more grails wastes time and momentum.
Trading is also an option. Phantasm Cores and other crafting materials can be acquired through player-to-player trades, which may save significant time if you find someone willing to deal.
Servant Race Stats and Why It Matters Beyond Crafting
The Servant Race isn't just a crafting gate — it provides substantial combat bonuses that complement the King of Heroes fighting style well.
| Stat Boost | Value |
|---|---|
| Max HP | +75% |
| Damage | +67% |
| Melee Damage | +17% |
| Lifesteal | +4% |
| Damage Reduction | +10% |
These buffs stack with the +30% damage buff from using the Babylon Key, making the Servant Race a natural pairing for anyone running the Gilgamesh fighting style long-term.
Using the Babylon Key to Unlock the F Move
Step 1: Open your inventory after crafting the key.
Step 2: Navigate to the Items section and find the Babylon Key.
Step 3: Click on the Babylon Key. A confirmation prompt will appear at the top of your screen.
Step 4: Press Yes to consume the key. The King of Heroes F move unlocks immediately, and the +30% damage buff applies to your build.
What the King of Heroes F Move Does
The F move is a large-radius AoE attack with high burst damage, accompanied by a distinctive yellow animation. It excels in both boss encounters and mob-clearing scenarios, making it one of the most versatile offensive abilities in Sailor Piece. Combined with the permanent +30% damage buff that comes with the unlock, it represents a significant power spike for any Gilgamesh build.
Frequently asked questions
Can I get the Babylon Key without the Servant Race?
No. The Servant Race must be equipped when you interact with the Babylon Key Crafter NPC. Without it, the crafting option won't work.
Do I need to craft the Babylon Key more than once?
No. It's a one-time unlock. Once consumed, the F move and damage buff are permanent on your character.
Where exactly is the Babylon Key Crafter?
On Boss Island, on top of the left palm area, next to the Divine Grail Crafter NPC.
Can I trade for Phantasm Cores instead of farming them?
Yes. All crafting materials, including Phantasm Cores, can be obtained through player trading.
The Babylon Key grind is one of the more demanding crafting goals in Sailor Piece, but the payoff — a permanent AoE ultimate and a 30% damage increase — makes it a defining milestone for anyone committed to the King of Heroes fighting style. Invest in your luck stat early, bank your Divine Grails, and the farming sessions will go considerably smoother.