The Frost Empress sword, also listed under its alias Rukia, is a Sea 2 King Update blade in Sailor Piece tied to a short quest line on Frost Island. You earn it by training against Quincy enemies, gathering Soul Fragments, and defeating the Frost Empress world boss. It sits high on the S+ watchlist, and the route is gated rather than random, so once you meet each requirement the sword is guaranteed.
Quick answer: Speak to the Soul Reaper Trainer NPC on Frost Island in Sea 2, defeat 50 Sea 2 Quincies, collect 20 Soul Fragments, then defeat the Frost Empress (Rukia) world boss. Return to the NPC to receive the sword.
Frost Empress sword requirements
The full unlock begins on Frost Island, around Quest 27, and runs entirely through that island’s content. Everything below must be completed before the Soul Reaper Trainer hands over the weapon.
| Requirement | Details |
|---|---|
| Starting NPC | Soul Reaper Trainer on Frost Island (Sea 2) |
| Training 1 | Defeat 50 Sea 2 Quincies |
| Soul Fragments | Collect 20 |
| World boss | Defeat the Frost Empress / Rukia world boss |
| Island | Frost Island |
How to unlock the Frost Empress sword
Frost Empress F move mastery (+300% damage)
After you own the sword, you can complete its mastery to unlock the F move. Unlike the standard +30% mastery bonus on most weapons, this one rewards an F move plus a +300% damage boost. The mastery quests are given by the Mastery NPC on a lonely snowy stretch of Frost Island.
| Requirement | Amount / Source |
|---|---|
| Clan | Kuchiki (equip via clan rerolls) |
| Weapon | Frost Empress sword |
| Ice Core | 1 (Ice Queen boss, ~0.5% drop) |
| Soul Fragments | 25 (Soul Reaper or Frost Empress) |
| Bankai Essence | 10 (Frost Empress drops) |
| Reward | F move and +300% Damage |
Note: The Ice Core is the hardest piece to secure because of its low drop rate from the Ice Queen boss in the First Sea. Expect a long stretch of repeated boss kills before one drops. The Bankai Essences come from the Frost Empress herself, so you will naturally accumulate some while farming her for Soul Fragments.
The sword itself is a fixed reward once the quest line is finished, so the only real variables are how quickly you farm Soul Fragments and how well your build handles the Frost Empress fight. Stack damage first, clear the Quincy training while you gather fragments, then take the boss down once to wrap up the route. If you plan to chase the +300% mastery, start rerolling for the Kuchiki clan early so the only bottleneck left is the rare Ice Core.
