How to Get Moon Slayer in Sailor Piece

Moon Slayer is one of the most visually striking fighting styles in Sailor Piece right now — think Kokushibo-level aesthetics with crescent slashes, purple craters, and a cutscene finisher that wipes entire mobs. The damage numbers back it up too: the F-move alone hits 15+ billion on a properly built character, and on maxed setups players report numbers reaching 43–65 billion. Getting there takes some work, but here's the full path from zero to unlocked.

What Is Moon Slayer?

Moon Slayer is a late-game melee fighting style available on Boss Island, officially inspired by Kokushibo from the Demon Slayer franchise. Despite displaying a sword-like weapon in your hand, it's classified as a fighting style — not a sword — so it scales with melee stats rather than sword damage. It's currently one of the strongest options for boss farming in the game, with standout burst damage and AoE moves that hold up in both mob clearing and single-target fights.

If you're wondering how to get Kokushibo in Sailor Piece — Moon Slayer is the in-game name for both the boss and the melee spec.

Where to Get Moon Slayer

Everything you need is on Boss Island. The Moon Slayer NPC who sells the style is there, the Boss Summoner NPC is there, and the Moon Slayer boss itself spawns there. You won't need to travel much once you arrive — it's a self-contained grind loop on a single island.

Requirements to Unlock Moon Slayer

To purchase the fighting style from the NPC, you need all of the following:

The Six-Eyed Demon title is the one that will take the longest. It only drops from defeating the Moon Slayer boss and carries an 85% damage buff — the highest title bonus in the game currently. With the pity system capping at 155 boss kills, you're guaranteed the title eventually, but it can take a while.

Upper Seals are a separate grind. They drop from enemies anywhere in the game, but Lawless Island is the most efficient spot because of the Arena Fighter density and respawn speed. Farm a large stack before heading to Boss Island — you'll need them both for crafting and for summoning the boss repeatedly.

How to Summon the Moon Slayer Boss

Head to Boss Island and interact with the Boss Summoner NPC. Scroll to find Moon Slayer in the boss list and submit the summoning cost. The cost scales with difficulty — higher difficulty means better drop rates on all materials:

Stick to Easy or Medium until your build can handle the damage output comfortably. Once you're there, Hard and Extreme are the most efficient per seal spent. The boss has over 1.25 billion HP on Easy, so bring your strongest gear — best sword or spec, maxed skill tree nodes, clan buffs, and damage titles active before you engage.

Moon Slayer Moveset

Once unlocked, here's what each keybind does and what damage it delivers on a well-built character:

M1 — Basic slashing combo that emits crescent moon particles with each hit.

Z Key (~2 billion damage) — Forward slash followed by a powerful somersault strike. Your character moves during the animation, which can be awkward for stationary mob farming but works well on bosses.

X Key (~2.2 billion damage) — Two slashes into a continuous forward slashing sequence. You stay stationary throughout, making it cleaner for precise positioning.

C Key (5+ billion damage) — Lifts the enemy with a swing, then fills the surrounding area with purple craters. Large AoE range makes this the go-to skill for clearing mob waves.

V Key (10+ billion damage) — A cutscene move where you unleash a massive ground-level cut that demolishes everything in front of you. Long cooldown but exceptional burst for boss phases.

F Key (15+ billion damage) — Summons a black domain around you, followed by continuous slashes and a final forward burst. The single hardest-hitting ability in the kit. Long cooldown, but it can effectively delete bosses instantly when timed right.

How to Unlock the Moon Slayer F Move

The F move is locked when you first get the style. To unlock it, find the Moon Slayer Master NPC — he sits on top of the hand sculpture with its palm facing down, on the right side of Boss Island. Submit the following:

• Moon Slayer fighting style (already equipped)
• Upper Clan (mandatory)
• 2x Moon Crest
• 10x Crescent Shards
• 85x Upper Seals

The Upper Clan is the main obstacle. It's a legendary-tier clan obtained through Clan Rerolls, and there's no workaround — you must have it equipped to unlock the F move. Its stats: +40% Damage, +50% Max HP, +12% Melee Damage, +12% Luck, plus a passive that gives a 20% chance on each skill use to deal +25% damage for 8 seconds. Once the F move is unlocked, you also gain an additional +30% damage bonus on top of the style's base output.

The additional Moon Crests and Crescent Shards come from continued boss farming, so by the time you've completed the main unlock, you'll likely already have a portion of what you need.

Recommended Build Tips

Before running Moon Slayer in serious content, a few things worth doing:

• Roll a Damage V passive on the melee if possible — it significantly increases output across all moves.

• Max your melee stat nodes in the skill tree. The style scales purely off melee, so every point there is a direct damage upgrade.

• The C move is your primary farming tool for mob waves. Z and X work better for single targets. Save V and F for boss burst windows.

• Consider rolling Colossus or Cursebrand from the Power system on Lawless Island — both add meaningful damage multipliers that stack directly with Moon Slayer's output.

Is Moon Slayer Worth Getting?

For endgame players focused on boss farming — yes, without question. The damage ceiling is the highest of any current fighting style, the Six-Eyed Demon title alone is worth grinding for its 85% damage buff, and the F move turns most boss encounters into a short fight. The grind to get there is long, but nothing about the power level is overhyped.