The Reaper Key is the summon item for the Black Reaper boss in Sailor Piece, and it has a single purpose: spawning that fight so you can grind the Black Reaper melee fighting style. It is a legendary-rarity drop locked behind Sea 2 progression and a side quest, with a base drop rate noticeably lower than most other legendary items in the game.
Requirements before farming Reaper Keys
Isolation Island is gated behind two progression steps. Without both completed, the teleport option will not appear in your map menu.
Step 1: Unlock Sea 2. This is the standard mid-game transition quest and is mandatory before any Sea 2 island becomes reachable.
Step 2: Complete the Blood Flowers quest. Collecting every Blood Flower across the Sea 2 region unlocks the Isolation Island teleport node.
Once both are cleared, open the map, select Isolation Island, and head toward the enemy spawns inside the area.
Where Reaper Keys drop
Reaper Keys come from a single enemy type. Killing other Sea 2 mobs will not work, and boss rooms or alternate game modes do not produce this drop.
| Detail | Value |
|---|---|
| Source enemy | Ghoul Member / Ghoul Master NPCs |
| Location | Isolation Island (Sea 2) |
| Rarity | Legendary drop |
| Use | Summon Black Reaper boss |
| Scaling | Higher boss difficulties consume more keys per summon |
How to improve the Reaper Key drop rate
The base drop chance sits well below other legendary items in Sailor Piece, so stacking Luck is the only meaningful way to shorten the grind. The key still drops without a Luck build, but expect long stretches between pulls.
- Equip Luck-boosting titles and runes before pulling enemies.
- Slot your strongest fast-hitting weapon to clear mobs quickly between resets. Gilgamesh V works well for continuous auto-farming.
- Turn on auto skill for whichever melee or sword you are using so you can chain kills without manual input.
What Reaper Keys are used for
The Reaper Key has exactly one function. You hand them over to summon the Black Reaper boss, who drops the materials needed to unlock the Black Reaper melee fighting style. Each difficulty tier of the summon requires a higher key count, so stockpiling before you start the boss grind is the practical approach. Going in with the bare minimum almost always means a return trip to Isolation Island mid-grind.
If you are still building toward a Luck setup, redeeming current Sailor Piece codes can help you roll better races, clans, and rerolls that feed into a stronger farming loadout.
Common reasons the key does not drop
If you have been farming for a long stretch with nothing to show, check these specific conditions before assuming bad luck:
- You are killing the wrong enemy type. Only Ghoul Member / Ghoul Master NPCs on Isolation Island drop the key.
- Your Luck stat is unbuffed. The base rate is low enough that running without Luck gear makes the grind significantly longer.
- You have not actually completed Blood Flowers and are farming a different Sea 2 island by mistake.
Once you have a working stack of Reaper Keys, return to the Black Reaper summon and start the boss grind. The keys themselves serve no other purpose, so there is no reason to hoard beyond what you need for the difficulty tier you plan to clear.