Radiant Rune is another secret rune added in the latest Sailor Piece update, and just like Primordial Rune, it’s designed as a rare, high-value drop that requires serious grinding.
If you’re planning to farm it, you need to understand one thing early:
This is not a quick farm—it’s a consistency-based grind.
Where to Get Radiant Rune
Radiant Rune is obtained exclusively from:
Infinite Tower (Tower Island)
There are no side methods, quests, or shortcuts. Everything revolves around this mode.
Step 1 – Get Tower Keys
Before entering the Infinite Tower, you need Tower Keys, which act as your entry requirement.
The most efficient way to farm them is by defeating high-level NPCs, especially on:
- Lawless Island
- Ninja Island
Stronger enemies give better results over time, so always prioritize areas where you can farm quickly but still face higher-tier mobs.
Step 2 – Enter Infinite Tower
Once you have a key, head to Tower Island and enter the Infinite Tower.
From here, your goal is simple:
- Climb as many floors as possible
- Survive longer runs
- Repeat the process
As you progress, enemies and bosses get stronger, making each run more challenging.
Drop Rate
Radiant Rune has:
Less than a 1% drop chance
That means:
- You won’t get it quickly
- You’ll need multiple runs
- RNG plays a big role
This is designed as a long-term grind, not a guaranteed reward.
How to Farm Efficiently
The biggest mistake players make is focusing only on luck. In reality, farming Radiant Rune is about maximizing attempts and efficiency.
Each run gives you multiple chances, so:
- The higher you climb → the more chances per run
- The faster you clear → the more runs per hour
This creates a simple but powerful loop:
- Farm keys
- Enter tower
- Push as far as possible
- Repeat consistently
To improve your farming efficiency, focus on your build.
A strong setup should:
- Clear waves quickly (good AoE)
- Handle bosses reliably
- Keep you alive in higher floors
Because reaching deeper floors increases your total drop opportunities within a single run.
Many players slow their progress without realizing it.
Farming weak NPCs for keys might feel easier, but it reduces your overall efficiency. Entering the tower with weak builds also limits how far you can go, lowering your chances per run.
Another mistake is expecting quick results. With such a low drop rate, quitting early guarantees failure.