Runes are passive boosts in Sailor Piece that change how hard you hit, how long you survive, and how often rare loot drops. You equip one at a time, and the right pick can swing a boss fight or a long farming session in your favor. Almost all of them come from a single place, with two rare exceptions tucked away in the Infinite Tower.
Quick answer: Reach Level 5,000, clear the Dungeon Master quest on Dungeon Island (collect 6 Ancient Puzzle pieces and defeat 25 bosses), then use a Dungeon Key to run the Rune Dungeon. Runes drop as random rewards from clearing its 15 waves.
Requirements to unlock the Rune Dungeon
Before any rune can drop, you need access to Dungeon Island and the gear to clear waves quickly. Three conditions gate the whole system.
- Be at least Level 5,000
- Collect 6 Ancient Puzzle pieces scattered across the map
- Defeat 25 bosses
You also need a Dungeon Key to spawn each run. Keys drop from World Bosses out in the open world, and the chance varies by boss. Most World Bosses can drop one, with the Shadow Boss being the exception that never does. Keys are not guaranteed, so killing bosses repeatedly is the real bottleneck for most players.
How to farm runes in the Rune Dungeon
Runes are not a guaranteed reward, so expect to run the dungeon many times. Teaming up with other players makes the waves far easier to clear, and the highest difficulty you can finish comfortably is always the best place to farm. Drop rates climb steadily across the waves; Suppression on Extreme, for example, goes from 3.39% on Wave 1 up to 8.85% by Wave 15.
All Sailor Piece runes and their stats
Nine runes drop from the Rune Dungeon, and none is rarer than another inside it. Which one you get is random. Two additional Secret runes, Primordial and Radiant, only come from the Infinite Tower. Every rune levels to a maximum of 50, and the numbers below show base and max-level values.
| Rune | Image | Base Buff | Max Level Buff |
|---|---|---|---|
| Havoc Rune |  | +55% DMG (x1.55) | +82% DMG (x1.82) |
| Wrath Rune |  | +40% DMG (x1.4) | +59% DMG (x1.59) |
| Destruction Rune |  | +25% DMG (x1.25) | +37% DMG (x1.37) |
| Inferno Rune |  | Burn for 70% of total DMG for 4 seconds | Burn for 104% of total DMG for 4 seconds |
| Blood Rune |  | Bleed for 65% of total DMG for 5 seconds | Bleed for 97% of total DMG for 5 seconds |
| Frost Rune |  | Stun 2 seconds + 30% DMG | Stun 3 seconds + 44% DMG |
| Guardian Rune |  | +39% Max HP (x1.39) | +59% Max HP (x1.59) |
| Fortune Rune |  | +10% Luck | +15% Luck |
| Suppression Rune |  | 10% DMG Reduction | 15% DMG Reduction |
| Primordial Rune |  | +84% DMG (x1.84) | +120% DMG |
| Radiant Rune |  | +16% Luck | +28% Luck |
For pure damage from a rune you can actually farm, Havoc is the strongest at +82% max. Inferno reaches a higher number on paper, but that 104% applies only to burn damage over four seconds, not your whole output, so it serves status-effect builds rather than raw DPS. Fortune is the dungeon pick for drop hunting, and Guardian is the choice when you keep dying to bosses.
Secret runes from the Infinite Tower
The Primordial and Radiant runes belong to the Secret rarity and never appear in the Rune Dungeon. You reach the Infinite Tower by handing a Tower Key to the Infinite Tower NPC on Tower Island, found between the Tower Upgrades and Tower Shop NPCs. Inside, you climb floors against growing enemy waves, picking up debuffs every fifth floor.
| Rune | Drop chance | Guaranteed at |
|---|---|---|
| Primordial | 0.002% to 0.013% | Floor 10,000 |
| Radiant | 0.0025% to 0.0135% | Floor 7,500 |
Both chances rise the higher you climb. Primordial gives the biggest damage boost in the game at max level, and Radiant is the top luck rune for farmers. Because the odds are tiny, most players climb with an auto setup and a luck build, often overnight. You can also trade for either rune with another player on your server using the in-game Trade button.
How to equip a rune
You can only have one rune active at a time. Swapping is safe; the rune you take off returns to your inventory. A single rune’s stat sits somewhere between its base and max value, so equipping your highest-leveled copy is always best.
How to level up runes
Runes level through duplicates. Each duplicate of the same rune grants one EXP, and the cap is level 50. Reaching the max requires 502 copies of that rune in total, which makes maxing one a long grind rather than an afternoon’s work.
There is no manual upgrade button. EXP is counted automatically, and the level gain applies to every copy of that rune you hold at once. Keep every duplicate you find, since even a base-level rune already gives a noticeable boost while you build toward the cap.
You’ll know the system is working when your equipped rune’s value climbs in your character stats after repeated dungeon clears. If runs feel slow, upgrade your gear first so you clear waves faster, run the highest difficulty you can finish reliably, and bring a group to take down World Bosses and keep your Dungeon Key supply steady.
