The Shadow Monarch sword in Sailor Piece has extremely powerful skills that destroy enemies and bosses within a few seconds. Yet, its most powerful F-skill is locked until you complete the sword’s Mastery questline. The Shadow Monarch Mastery quests require you to complete dungeons on a particular difficulty, kill Shadow Soldiers, and obtain the rare Monarch Clan from the gacha.
Here’s how you can finish the Shadow Monarch Mastery quests and unlock the weapon’s ultimate skill in Sailor Piece.
How to start the Shadow Monarch Mastery questline in Sailor Piece

The Mastery questline can be started only after you acquire the Shadow Monarch sword in Sailor Piece. This endgame weapon is given by the Shadow Monarch NPC, located on Dungeon Island, after you obtain the Jinwoo sword and the required currencies and items for purchasing the sword.
Items for buying the Shadow Monarch weapon are acquired from the Double Dungeon. Speak to the NPC inside the building on Dungeon Island and use a Dungeon Ticket to enter the Double Dungeon.
After obtaining the Shadow Monarch sword, unlock its Mastery quests by speaking to the Shadow Monarch Master NPC. This character is at the edge of Starter Island, past the Thief enemies and the tree that has a Slime Piece.
All Shadow Monarch Mastery quests in Sailor Piece

The Shadow Monarch Master gives three sequential quests. You must complete each of them to unlock the F move of the Shadow Monarch weapon.
- Dungeon Master: Win 10 Double Dungeons on Hard or Extreme difficulty.
- Monarch’s Blood: Obtain and equip the Monarch Clan.
- Shadow Army: Defeat 25 Shadow Soldiers in the dungeon.
The Monarch Clan can be obtained by using Clan Rerolls. Given that this Legendary-rarity Clan has a low appearance rate in the gacha, you may need to use hundreds of rerolls to eventually get Monarch.
Shadow Soldiers can spawn in any wave but they have an extremely low spawn rate in the Double Dungeon. So, you may need to repeat the dungeon battles multiple times to ultimately finish the quest.
Once all Mastery quests are completed, the Shadow Monarch sword’s F skill will be unlocked, and your weapon will also receive a 30% damage buff. Use the new skill to swiftly win all your battles, as it creates a barrage of slashes that deal huge damage to the targets.
Also check: Sailor Piece Aizen Mastery questline guide
FAQs on Sailor Piece
Where is the Shadow Monarch Master?
This NPC can be found on Starter Island. After using the portal to enter the island, take the stairs to the Thief enemies. You’ll find the Shadow Monarch Master standing on a rock behind the Thief mobs.
When do Shadow Soldiers spawn?
Shadow Soldiers can appear in any wave inside the Double Dungeon. They have an extremely low spawn chance.
What buffs does the Monarch Clan offer?
Equipping the Monarch Clan gives you 27% Damage, 40% Max HP, 7% Sword Damage, 10% Luck, and 20% Chance for an additional drop from enemies.
Edited by Spandan Chatterjee