The Shadow Sword F Move in Sailor Piece is unlocked by completing a six-quest mastery chain. You must already own the Shadow Sword before starting this progression. The mastery quests test damage output, NPC farming, boss fights, and dungeon clears across three difficulty tiers. Finishing all six quests grants the F Move and a permanent 30% damage increase.
Quick answer: Travel to Starter Island, speak with the Shadow Mastery NPC, and complete six quests in order: deal 1 billion damage, defeat 1,250 NPCs, defeat 150 bosses, and complete 10 CID dungeon runs each on Easy, Medium, and Hard mode.
Obtain the Shadow Sword first
The mastery quests are locked until you acquire the Shadow Sword. To obtain it, collect the following materials by running the CID dungeon on Dungeon Island:
| Material | Quantity |
|---|---|
| Atomic Core | 1 |
| Shadow Essence | 4 |
| Void Seed | 8 |
| Umbral Capsule | 20 |
You also need the Shadowborn race equipped, which is a legendary race obtained through race rerolls. Once you have all the materials and the correct race, go to Dungeon Island and find the Shadow Trainer NPC on the roof. Exchange the materials, 10 million money, and 15,000 gems for the Shadow Sword.
Start the mastery questline on Starter Island
With the Shadow Sword in your inventory, travel to Starter Island and locate the Shadow Mastery NPC. Interact with this NPC to receive the first of six quests. Each quest tracks a specific requirement and must be completed in sequence.
Quest 1: Deal 1 billion damage
The first quest requires you to accumulate 1,000,000,000 total damage. This damage counts across all enemies and bosses. Soul Society Island is the most efficient location for this quest because high-level NPCs have large health pools, allowing you to rack up damage quickly. Use your strongest abilities and focus on enemies that survive multiple hits rather than one-shot targets.
Quest 2: Defeat 1,250 NPCs
The second quest requires 1,250 NPC kills. Starter Island is the best location for this objective. The thief NPCs here are low-level, spawn frequently, and die in one or two hits. Set up auto-skill targeting and farm in a high-density spawn area to complete this quest quickly.
Quest 3: Defeat 150 bosses
The third quest requires you to defeat 150 bosses. Travel to Boss Island and use boss keys to spawn bosses on demand. The Saber boss is the most efficient choice because it has relatively low health and can be defeated quickly with the Shadow Sword's abilities. Enable auto-spawn if available and farm until you reach 150 kills.
Quest 4: Complete 10 CID dungeons on Easy Mode
The fourth quest requires 10 completions of the CID dungeon on Easy difficulty. Go to Dungeon Island, speak with the Dungeon Master NPC, and select the CID dungeon. Choose Easy mode from the difficulty menu. Easy runs are fast and straightforward, making this the quickest of the three dungeon tiers.
Quest 5: Complete 10 CID dungeons on Medium Mode
The fifth quest increases the difficulty to Medium mode. You must complete 10 runs on this tier. Enemies deal more damage and have higher health compared to Easy mode. Use strong gear and abilities to clear waves efficiently. If you struggle to survive, consider teaming up with other players or upgrading your equipment before continuing.
Quest 6: Complete 10 CID dungeons on Hard Mode
The final quest requires 10 completions on Hard mode. This is the toughest tier of the mastery challenge. Enemies hit harder and take significantly longer to defeat. Coordinate with teammates or optimize your build for survivability and damage output. Hard mode runs can be slow, so expect this quest to take the most time.
Claim the F Move and damage buff
After completing all six quests, return to the Shadow Mastery NPC on Starter Island. The NPC will confirm that the mastery challenge is complete. The Shadow Sword F Move unlocks automatically at this point, and you receive a permanent 30% damage buff that applies to all combat. The F Move is a powerful area-of-effect ability that deals high damage and has a moderate cooldown.
Verification and rewards
You can verify the unlock by equipping the Shadow Sword and checking your ability bar. The F Move appears as a new skill slot. The 30% damage buff is passive and does not require activation. You will notice increased damage numbers immediately in combat. If the F Move does not appear, confirm that all six quests show as completed in your quest log and speak with the Shadow Mastery NPC again.
The Shadow Sword F Move significantly improves the weapon's effectiveness for boss fights, dungeon runs, and general farming. The permanent damage buff stacks with other bonuses and makes the Shadow Sword one of the strongest progression weapons in Sailor Piece.