Crystal Defense is the wave-based mode added to Sailor Piece in the Anti Magic update, sitting on Punch Island in Sea 2. You defend a central crystal from waves of enemies, earn Crystal Coins, and chase drops like the Anti Magic sword, Demon Wings accessory, and Demon Dweller title.
Where Crystal Defense is located
The mode lives on Punch Island in Sea 2. Take the portal into Sea 2, head to Punch Island, and follow the road on the left past the Fast Ninja NPCs. Keep walking, and you will see three NPCs standing on glowing pads with a leaderboard nearby. The spot is northwest of the Cosmic Being world boss arena.
The three NPCs handle different jobs. The Defense Merchant sells items for Crystal Coins, the Defense Upgrades NPC sells permanent stat boosts, and the Crystal Defense NPC opens the portal into a run.
How to get Crystal Keys
You need a Crystal Key every time you start or retry a run. Keys drop from any NPC across Sea 2, with drop rates scaling on your luck stat.
The fastest farming spot is Sea 2 Starter Island. Park between two NPC spawn clusters and use a wide AoE skill to clear them on repeat. Quake Fruit's C move is the most popular pick because it hits every nearby enemy in one cast. Stack a few keys before a session so you can retry without breaking your loop.
How a run works
You enter the portal alone or with up to four players. A vote prompt appears before the run begins, so set your build before voting in. The crystal sits in the middle at 100% HP, and enemies spawn from multiple lanes and walk toward it. Your job is to kill them before they reach the crystal.
Each wave applies a random debuff. Common ones include halved ability damage, longer cooldowns, and increased incoming damage. Every fifth wave spawns a boss with a chance to drop the Anti Magic sword, Demon Wings accessory, or Demon Dweller title. Drop rates scale with your luck stat.
You earn 1 to 4 Crystal Coins per cleared wave, again scaled by luck. If the crystal is destroyed, the run fails, and you spend another Crystal Key to retry. There is also an auto-restart toggle in the in-run settings where you can type a target wave for AFK farming.
Crystal Defense Merchant prices
Crystal Coins only spend at the Defense Merchant and Defense Upgrades NPCs. Here is the full Merchant price list.
| Item | Price (Crystal Coins) |
|---|---|
| Common Chest | 1 |
| Rare Chest | 5 |
| Epic Chest | 12 |
| Legendary Chest | 25 |
| Mythical Chest | 65 |
| Secret Chest | 500 |
| Aura Crate | 1,000 |
| Cosmetic Crate | 1,400 |
| Boss Key | 3 |
| Dungeon Key | 3 |
| Tower Key | 8 |
| Trait Reroll | 4 |
| Race Reroll | 4 |
| Clan Reroll | 9 |
| Bloodline Stone | 14 |
| Clover Outfit | 850 |
| Destroyer Aura | 2,000 |
| Anti Magic | 5,000 |
Anti Magic at 5,000 coins is the headline buy. The Clover Outfit and Destroyer Aura are cosmetic-leaning, while Bloodline Stone at 14 coins is the cheapest reliable source in the game right now.
Crystal Defense Upgrades shop
The Defense Upgrades NPC sits next to the Merchant and sells permanent account-wide stat tracks. Each track has five levels. Maxing every track costs 43,350 Crystal Coins in total.
| Stat | L1 | L2 | L3 | L4 | L5 | Total | Max value |
|---|---|---|---|---|---|---|---|
| Damage | 850 | 1,150 | 1,500 | 2,000 | 3,000 | 8,500 | +25% (5%/lvl) |
| Crit Damage | 850 | 1,150 | 1,500 | 2,000 | 3,000 | 8,500 | +15% (3%/lvl) |
| Crit Chance | 850 | 1,150 | 1,500 | 2,000 | 3,000 | 8,500 | +5% (1%/lvl) |
| HP | 600 | 750 | 1,000 | 1,250 | 1,750 | 5,350 | +37.5% (7.5%/lvl) |
| Luck | 1,250 | 1,750 | 2,250 | 3,000 | 4,250 | 12,500 | +15% (3%/lvl) |
HP is the cheapest track to finish and the easiest survivability boost. Luck is the most expensive track but pays itself back through better coin gen and better boss-wave drop chances. Crit Chance has the worst value per coin, so save it for last.
Rewards you can pull from runs
Two reward streams come out of Crystal Defense. The first is the coin shop, where everything is purchasable with Crystal Coins. The second is the boss-wave drop pool, which rolls every fifth wave.
- Anti Magic (sword, Mythical): Buy for 5,000 coins or roll it from a boss wave.
- Demon Wings (accessory): Boss-wave drop only.
- Demon Dweller (title, +100% damage): Boss-wave drop only, not in the shop.
- Clover Outfit: Cosmetic accessory, 850 coins.
- Destroyer Aura: Cosmetic aura, 2,000 coins.
Drop rolls are independent for each boss wave. Deeper runs equal more rolls, so pushing further matters more for Demon Wings and Demon Dweller than for Anti Magic, which you can simply buy.
Build priorities for clearing waves
Crystal Defense punishes single-target setups. Wave clear, range, and uptime matter more than burst on one target. AoE swords and melee specs that knock enemies back are the strongest picks because they buy the crystal extra time.
Strong weapon options include Ice Queen (V move has long range, knockback, and a low cooldown), The World (knockback plus large AoE), Dragon Goddess (high overall damage), and Cosmic Being melee for early-wave clear. Great Mage and Gilgamesh melee work as backups but have longer downtime between casts.
For accessories and runes, prioritize survivability into the late waves. Damage reduction multiplies with HP, so a defensive accessory plus a damage rune like Primordial holds up better than stacking pure DPS. Equip your strongest title and bloodline before voting to start.
Auto-restart and AFK farming
The mode supports auto-restart from the in-run settings. Pick the wave you reliably clear, type it in, and the mode will reset the run when you fail past that point, spending one Crystal Key per restart.
Stack 5 to 10 keys before starting an AFK session so you do not run out mid-loop. Standing slightly off the crystal is better than standing on top of it, since some enemy AoE attacks can clip the crystal through your hitbox.
Co-op scaling
Up to four players can share one instance. Wave HP scales with player count, which means more enemies and more total Crystal Coins per wave. With a coordinated squad, this is the fastest coin-per-hour route in the game right now. To join a friend's run, walk up to their portal and hold E to enter as the host's session.
Spending order if you are starting fresh
If you are entering the mode for the first time, the cleanest spending order is Anti Magic first at 5,000 coins, then the HP upgrade track at 5,350 coins for survivability, then Damage at 8,500, then Luck at 12,500 to snowball coin and drop gains. Crit Damage and Crit Chance come last. Cosmetic buys like Clover Outfit and Destroyer Aura are flexible and can slot in whenever.
If you already have Anti Magic from a lucky boss drop, skip straight to the upgrade tracks, since they apply across your whole account and not just inside Crystal Defense.