Crystal Coins are the gatekeeper currency for the Anti-Magic content in Sailor Piece, funding the Anti Magic sword, the Destroyer Aura, the Clover Outfit, and every permanent stat upgrade tied to Crystal Defense. They drop from one place only, and the grind is long enough that build choice and run consistency matter more than raw playtime.
Where Crystal Defense is and what you need to enter
Crystal Defense sits on Punch Island in Sea 2. From the Punch Island spawn, take the left road past the Fast Ninja NPCs and continue straight, northwest of the Cosmic Being world boss. Three NPCs and a leaderboard mark the spot: the Defense Merchant, the Defense Upgrades NPC, and the run starter.
Entry costs one Crystal Key per attempt. Keys drop from NPCs across Sea 2 at a low rate, so you will want a stockpile before settling in for a long session. Up to four players can join a single run.
How Crystal Coins drop
You earn Crystal Coins by clearing enemy waves while keeping the central crystal alive. Each wave pays out 1 to 4 coins, and the per-wave payout scales as you push deeper floors. Higher Luck increases the coin roll within that range, but Luck does not affect boss loot drops inside Crystal Defense, so a pure damage build is the correct choice for coin farming.
Every fifth floor spawns a boss with a chance to drop the Anti Magic sword, the Demon Wings accessory, and the Demon Dweller title. Those drops scale with Luck on the bosses themselves, but coin throughput is a function of how fast you clear waves.
Best build and weapons for clearing waves
Run your highest pure-damage loadout. Drop-rate setups are a trap here because Crystal Defense coin and item rolls inside the run favor damage uptime over Luck. Wide AoE V-skills are the priority because enemies spawn from multiple lanes and rush the crystal at once.
| Weapon / Fruit | Why it works |
|---|---|
| Ice Queen | Long-range V with fast cooldown, knocks enemies back from the crystal. |
| Cosmic Being | Large purple AoE on V, strong single-cast clears. |
| The World | High damage AoE, useful for boss waves on floor multiples of 5. |
| Dragon Goddess | Wide V-skill arc that covers spawn lanes. |
King of Heroes was previously a popular pick for stationary farming, but the V-skill now drifts the character forward after casting. It still works if you face a solid wall or the crystal itself to block movement, but the listed weapons above are safer for AFK setups.
AFK setup for overnight farming
Step 1: Stockpile Crystal Keys on Sea 2 Starter Island. Equip a luck build, stand on the central spawn marker, and spam an instant-cooldown wide attack to one-shot spawning NPCs. Keys drop alongside Relic Parts during this farm.
Step 2: Enter Crystal Defense and position yourself on top of the crystal with one of the wide-AoE weapons listed above. Set your V-skill to auto-fire so the ability cycles on cooldown without input.
Step 3: Open the run settings and enable Auto Replay. When the crystal eventually falls, the game spends one Crystal Key and restarts the run automatically. Pick a comfortable target floor so the loop fails predictably rather than stalling on impossible waves.
What Crystal Coins buy
Two NPCs spend the currency: the Defense Merchant for items and the Defense Upgrades NPC for permanent stat increases. Anti Magic at 5,000 coins is the headline purchase for unlucky players who never see the boss drop, while the Destroyer Aura and Clover Outfit are the next priority cosmetics with stat value.
| Item | Price (Crystal Coins) |
|---|---|
| Common Chest | 1 |
| Rare Chest | 5 |
| Epic Chest | 12 |
| Legendary Chest | 25 |
| Mythical Chest | 65 |
| Secret Chest | 500 |
| Boss Key | 3 |
| Dungeon Key | 3 |
| Tower Key | 8 |
| Trait Reroll | 4 |
| Race Reroll | 4 |
| Clan Reroll | 9 |
| Bloodline Stone | 14 |
| Clover Outfit | 850 |
| Aura Crate | 1,000 |
| Cosmetic Crate | 1,400 |
| Destroyer Aura | 2,000 |
| Anti Magic | 5,000 |
Permanent upgrade costs to max every stat
The Defense Upgrades NPC sells five stat tracks, each with five levels and escalating costs. Maxing every track requires 43,350 Crystal Coins. Damage and Luck are the priority pulls because Damage compounds your wave clear speed, and Luck improves boss loot rolls outside the run.
| Stat | L1 | L2 | L3 | L4 | L5 | Total | Max bonus |
|---|---|---|---|---|---|---|---|
| Damage | 850 | 1,150 | 1,500 | 2,000 | 3,000 | 8,500 | +25% |
| Crit Damage | 850 | 1,150 | 1,500 | 2,000 | 3,000 | 8,500 | +15% |
| Crit Chance | 850 | 1,150 | 1,500 | 2,000 | 3,000 | 8,500 | +5% |
| HP | 600 | 750 | 1,000 | 1,250 | 1,750 | 5,350 | +37.5% |
| Luck | 1,250 | 1,750 | 2,250 | 3,000 | 4,250 | 12,500 | +15% |
Build pieces that speed up the grind
Bloodline and Clan rerolls pay for themselves over a long farm. Demonic Bloodline grants 32% damage and a 12% sword damage multiplier, edging out Astral for sword builds. Devil Clan provides 42% damage, 12% sword damage, and a luck boost that beats Eminence for sword players who still want drop-rate value while farming keys outside the tower.
Verifying that everything is configured correctly is straightforward. Open the Stats menu before voting to start, confirm your damage percentage is on your saved damage build, and check that Auto Replay is ticked in the run settings. If the Defense Upgrades NPC shows your stat track at level 5 with no further upgrade option, that track is maxed.