How to Get All Demon Slayer Swords in Reign Piece Guide!

The Demon Slayer update in Reign Piece introduced powerful swords inspired by popular characters, each locked behind specific bosses, materials, and raid content. These weapons are not handed out casually. You will need grinding, raids, and a bit of patience to collect them all. This guide explains every requirement clearly so you do not waste time farming the wrong thing.

Where to Start the Demon Slayer Content

All Demon Slayer sword NPCs are located on Tengen’s Hideout Island. This island is the main hub for Demon Slayer-related content, including weapon sellers and progression paths. Before attempting to unlock any sword, make sure you have access to this island and can comfortably fight mid-to-late-game bosses.

Infinity Castle Key Explained

The Infinity Castle Key is required to access the Infinity Castle Raid, which is mandatory for obtaining the remaining Demon Slayer swords.

You can get the key in two ways:

• Random drops from the Zenitsu Boss
• Crafting the key at Shibuya Crossing Island using key fragments

Once you have the key, you are ready to enter one of the most important raids in the update.

The Infinity Castle Raid functions like a dungeon with one major rule: you only get one life. If you die, the run ends. Bringing friends is strongly recommended unless you enjoy wasting keys. Inside the raid, you will fight Demon Slayer-themed bosses that drop materials for the remaining swords.

All Demon Slayer Sword Guide:

1. Zenitsu Sword Guide

The Zenitsu sword is usually the first Demon Slayer weapon players aim for, since it also unlocks access to later content. Requirements to Get Zenitsu Sword: To obtain Zenitsu’s sword, you will need:

• 12 Thunder Breathing Cores
• 3 Static Soul Orbs
• Sleepwalker Trait

All Zenitsu-related materials drop from the Zenitsu Boss. This boss can be spawned using crystals. Farming this boss repeatedly is required, as drops are not guaranteed every run. In addition to sword materials, the Zenitsu Boss can also drop Infinity Castle Key Fragments or, if you are extremely lucky, the full Infinity Castle Key.

2. Kaigaku Sword Guide

The Kaigaku sword is obtained entirely through the Infinity Castle Raid. Requirements to Get Kaigaku Sword, You will need:

• 15 Black Lightning Cores
• 1 Demon Blood
• Hybrid Race

Black Lightning Cores and Demon Blood drop from Kaigaku inside the Infinity Castle Raid. The Hybrid Race requirement must already be unlocked before attempting to claim the sword, so make sure your race meets the condition.

3. Tengen Uzui Sword Guide

Tengen’s sword is one of the flashiest Demon Slayer weapons and also requires Infinity Castle farming. Requirements to Get Tengen Sword, To unlock Tengen Uzui’s sword, you need:

• 20 Flash Sigils
• 10 Explosive Rhythm Fragments
• 2 Uzui Clan Relics

All required items drop from Tengen Boss fights inside the Infinity Castle Raid. This sword typically takes the longest to farm due to the number of materials needed and the raid’s one-life limitation.

Best Farming Tips for Demon Slayer Swords

To make the grind less painful:

• Farm Zenitsu Boss first until you secure an Infinity Castle Key
• Run Infinity Castle with a team, not solo
• Focus on one sword at a time to avoid inventory confusion
• Save keys and do not rush raids unprepared

Efficient runs matter more than rushing in undergeared.

Are Demon Slayer Swords Worth Getting?

Yes. All Demon Slayer swords offer strong damage, smooth animations, and excellent performance in raids and boss fights. When combined with advanced Haki stages, they become some of the strongest weapons currently available in Reign Piece. If your goal is endgame combat or efficient farming, collecting all Demon Slayer swords is absolutely worth the effort.

Unlocking every Demon Slayer sword in Reign Piece is a grind-heavy process, but it is also one of the most rewarding progressions in the game. From farming Zenitsu to surviving Infinity Castle runs, each step pushes players toward endgame strength. Take your time, farm smart, and eventually you will have all Demon Slayer weapons sitting comfortably in your inventory, judging newer players silently.