To upgrade swords in Blox Fruits, go to the Blacksmith NPC and trade the required materials for the weapon upgrade. Swords can be upgraded in every Sea, and the Blacksmith is found in places like Pirate Village, Kingdom of Rose, and Port Town depending on the Sea.

How it works

  1. Get the sword you want to upgrade.
  2. Collect the materials the Blacksmith asks for.
  3. Talk to the Blacksmith NPC.
  4. Select the sword and confirm the upgrade.

The upgrade usually increases damage, and each weapon can only be upgraded once.

Where to find the Blacksmith

  • First Sea: Pirate Village
  • Second Sea: Kingdom of Rose
  • Third Sea: Port Town

Materials

The exact materials depend on the sword, so different weapons need different item sets. Common examples mentioned in guides include things like Leather, Scrap Metal, Vampire Fangs, Shark Teeth, Fish Tails, and other dropped materials.

Useful note

You must have the sword ready in your inventory, and you need the required materials before the Blacksmith will upgrade it. Some guides also mention that all swords can be upgraded and that enchanted versions or extra effects are separate systems.

Quick Scoop

If you just want the short version: farm the materials, visit the Blacksmith, and upgrade the sword once for a damage boost.

TL;DR

Blox Fruits sword upgrades are done through the Blacksmith with specific materials, and the upgrade is usually a one-time damage boost per weapon.