The Rengoku is a highly coveted weapon in the “Blox Fruits” world. It is an “S” tier sword with legendary ranking. In a game where you are battling against both pirates and marines, you need to have the most powerful weapons to come out on top. The Rengoku is one of those rare weapons that you should get and capitalize on in Blox Fruits. Wielding the Rengoku allows you to deal significant damage to your enemies.

But it isn’t that easy to obtain this legendary sword. It’s hidden in a chamber beneath the Ice Castle in the Second Sea. To top things off, you’ll have to reach at least level 1,350 to unlock the Ice Castle.
In this guide, you’ll learn how to get the Rengoku in Blox Fruits.
How to Get the Rengoku
There are two ways you can obtain Rengoku. You can battle the Awakened Ice Admiral in the Ice Castle or fight Arctic Warriors or Snow Lurkers on Ice Castle Island. Either method will provide you with the Hidden key that will help you unlock the Rengoku. But, you’ll need to stock up well on your “S” tier devil fruits to ensure that you remain powerful and stay ready for battle.
Step 1 – Get a Hidden Key
The Awakened Ice Admiral route is the best chance to get a Hidden Key at 5%, but he’s a tough opponent. He’s a level 1,400 boss, so you need to bring you’re A-game if you want to take him on. The easiest way to win is by hitting him with a ranged move and running away to hide behind the castle walls. This will ensure that he isn’t able to fire back at you as you continue your attacks.
Talk to the Quest Frost Giver once you get to the Ice Castle to get him to spawn. He’ll allow you to select the opponent to get the Hidden Key.
Alternatively, you can go to Ice Castle Island and fight the Artic Warrior or Snow Lurker NPCs. This method is much easier than facing the Awakened Ice Admiral, but the chances of getting a Hidden Key drop to 0.5%.

Keep in mind that you may have to battle these enemies (or bosses if you go that route) multiple times before finally obtaining a key.
Also, the NPCs and the Awakened Ice Admiral drop both Hidden and Library keys. What you are looking for is the Hidden Key. The Library Key is blue and opens the door to “Death Step.”
Step 2 – Find the Secret Door and Chest
Regardless of the method, it’s time to get the Rengoku once you finally obtain a Hidden Key.
- Enter the main room.
- Go toward the red carpet that you will see to your right.
- Follow the hallway until you spot a stone wall to your left. It’s to the left side of the stairs and go through the secret door.
- Interact with the chest to open and retrieve the Rengoku Sword.
The Rengoku Skills
Wielding the Rengoku gives you two new abilities to help you deal more damage to enemies in Blox Fruits. But, they can only focus on a single target during attack. You can activate the following moves once you get the Rengoku:
Burning Slash

“Burning Slash” requires a Mastery Level 350 to unlock. “Burning Slash” allows you to attack your enemy by releasing a large streak of fire that moves horizontally on the ground dealing intense damage. Its effect tends to linger on long after the attack, further weakening the enemy. “Burning Slash” has a cool-down time of 15 seconds and can be activated by pressing the “X” button.
Demon Slayer

This move involves carrying out a quick attack on the enemy through strikes. You will need to unlock mastery level 150 to unlock it. “Demon Slayer” is known for the high physical damage it deals to the enemy. Your attack leaves a trail of orange and red hues in its wake. The move has a cool down time of 10 seconds and can be activated by pressing the “Z” key. “Demon Slayer’ works well with other moves you can find in Blox Fruits.
Limitations of the Rengoku Sword
The Rengoku is a highly revered sword in Blox Fruits and its skills are powerful. But, there are some drawbacks to this sword. Here are some of its limitations:
- The Rengoku “Demon Slayer” skill can’t deal damage to multiple enemies. This is quite disappointing considering how grueling the journey of getting the Rengoku is.
- The “Burning Slash” is quite slow. This means that enemies can easily escape its attack.
How to Upgrade the Rengoku
You can upgrade your Rengoku sword in the Blox Fruits world. You will need to interact with the Blacksmith NPC. He will upgrade the Rengoku with +8% damage if you have Magma Ore, Vampire fangs and scrap metal. Go to the First Sea under the big orange house near the Pirate Village or in the docks at the Second Sea to find the NPC.
Tips and Tricks to Get the Rengoku
The search for the Rengoku can be grueling. Here are a few tips and tricks to help you get the legendary weapon:
- You can increase your chances of getting the Hidden Key by purchasing a 2x Boss drops game pass.
- The Awakened Ice Admiral can use Ice Spears to attack. Use Observation, Flash Step, or continuously spam Dash to avoid the attack.
- When fighting the Awakened Ice Admiral, he can use Glacial Surge to knock you away. The most effective way to escape this attack is by keeping a safe distance. He will always use this ability when you are in the air.
- Absolute Zero is the last maneuver the Awakened Ice Admiral may use to defeat you. This skill allows him to touch the ground and turn it into ice, freezing anyone on it. Always fly above and launch attacks from the upper rooms of the Ice Castle to avoid this attack. Moving further away from him is wise because he always uses this ability when you’re in close range.
FAQs
What can you block the enemy from doing when you get the Rengoku?
The enemy can’t use the Haki of Observation with this sword. However, the effect only lasts for a short time.
Is the legendary Rengoku Sword great for close-range combat?
No. The abilities of the Rengoku are designed to attack the enemy from afar. It is, therefore, ideal for long-distance combat.
Which limitation will you face when using Demon Slayer?
“Demon Slayer” can only carry out one enemy attack at a time.
Apart from the Rengoku, which other way can you use to get more power in Blox Fruits?
You can collect devil fruits or learn a new fighting style to grow stronger in Blox Fruits.
Imagine How It Feels to Become a Samurai!
Inspired by the flame Hashira from the Demon Slayer Anime, the red fiery look of the Rengoku in Blox Fruits is deserving of a ‘Samurai” title. The Rengoku is a worthy addition to your weapon arsenal in Blox Fruits. If you’ve been looking for a way to become more powerful in the game, getting the Rengoku is a smart choice. As a demonic creation forged with fiery metals, it deals the second-highest damage to enemies in Blox Fruits.
Have you gotten the Rengoku? Which Rengoku skill have you activated? Let us know in the comments section below.
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