The Rengoku blade—famous for its aggressive moves, fiery animations, and ability to break Observation Haki—awaits you in the Second Sea. If you’re prepared for a bit of grinding and RNG, this streamlined guide will walk you through the fastest, most reliable way to earn it in 2025.

Pre-Requisites: Prepare for the Hunt

Before diving into the action, make sure you have the basics covered:

  • Reach Level 700+
    You’ll need to be at least Level 700 to enter the Second Sea (New World).
  • Find the Ice Castle
    Once you arrive in the Second Sea, head to the Ice Castle island—this is where your Rengoku journey begins.

Step 1: Collecting the Hidden Key

The Rengoku is sealed inside a hidden chest, and you’ll need the Hidden Key to open it. This key drops randomly from enemies on the Ice Castle island.

Farming Options

Awakened Ice Admiral (Boss) – Level 1400

  • Drop Chance: Around 5%
  • Why Farm It: This is the most reliable method. The boss respawns every 20 minutes, and using server hopping can dramatically speed up your attempts.

Arctic Warriors – Level 1350

  • Drop Chance: Approximately 0.5%
  • Why Farm Them: Great enemies to grind while the boss is on cooldown. Their lower level makes them easier and faster to dispatch.

Snow Lurkers – Level 1375

  • Drop Chance: Approximately 0.5%
  • Why Farm Them: Perfect for filling the downtime between boss spawns—quick kills, steady pace, and a small chance at the key.

Pro Tip for 2025:

If you’ve got Robux to spare, the 2x Boss Drop Game Pass makes getting the Hidden Key significantly faster. Combined with boss hopping, this is the most efficient method.

Step 2: Unlocking the Secret Chamber

Once the Hidden Key appears in your inventory, you’re just a few steps away from securing the Rengoku.

  • Enter the Ice Castle’s Main Room
    This is where the Awakened Ice Admiral spawns.
  • Find the Hidden Passage
    Use the stairs behind the room and look to the left of the red carpet.
  • Walk Through the Wall
    A specific wall section is passable—walk right through to enter a small hidden chamber.
  • Claim Your Reward
    Inside the chamber sits the Hidden Chest. Approach with the Hidden Key to unlock and obtain the Rengoku sword.

Bonus: You’ll also earn the stylish Samurai Title.

Rengoku Sword Moveset & Mastery

Rengoku is a deadly choice for PvP and PvE thanks to its fast attacks and Instinct-breaking abilities.

Z – Demon Slayer (150 Mastery)

A rapid dash attack followed by a flurry of fiery slashes that deal damage over time and hit multiple times.

X – Burning Slash (350 Mastery)

A large, sweeping AoE fire slash. Perfect for extending combos, dealing heavy damage, and disrupting enemy Instinct.

Powering Up Your Rengoku

Want even more damage? Visit any Blacksmith NPC across the Seas (e.g., Green Zone in the Second Sea) to enhance your blade.

Upgrade Benefits

  • +8% extra damage

Materials Needed

  • 8× Vampire Fangs — dropped by Vampires in the Third Sea’s Graveyard.
  • 20× Magma Ore — found in First & Second Sea magma-themed areas (Magma Village, Magma Admiral).
  • 15× Scrap Metal — a common drop across all Seas.