Mu Xiaokui Boss Guide: Unlocking the Secret Third Phase

Who Is Mu Xiaokui, Young Mistress of the Order?

Mu Xiaokui is the emotional core of the Village of Lu chapter and, per PCGamesN, “potentially the most visually impressive boss fight in Phantom Blade Zero.” She is the daughter of Soul’s master — he has known her since she was a child — and the Young Mistress side quest exists to make you feel that bond before the game asks you to break it. She is also the first three-phase fight in the game, but with a catch: the third phase only exists if you earn it.

This guide covers the ribbon hunt that unlocks her full fight, all three phases, and the reward chain that ends with the Fiend Saws. For the full roster, see our all bosses list.

Young Mistress: The Five Ribbons

Entering the Village of Lu automatically starts the Young Mistress side quest. Mu Xiaokui left five ribbons around the village, each triggering a short dialogue with Soul when collected. When you are close to one, listen for the sound of the bells tied to it — the audio cue is your real tracker. Per Polygon’s locations guide, the five are:

1. Bridge to the Well of the Three Puppets — unmissable; tied to a tree just after the Zhuo Bi, the Gatekeeper fight.
2. The covered bridge near the Well — blocked by threads until you kill the Puppet Spearman hidden in the upright coffin below.
3. The Lady Grounds bell — awarded automatically after beating Master Bi Yuan of the Tianxuan Sect.
4. Temple of Blue Fireflies — tied to a tree left of the temple entrance, across the bridge beside the locked door.
5. Beneath the Well — on the wooden walkway near the bell, reachable once the main quest opens the well.

Critical warning (games.gg): you must complete Young Mistress — including examining Mu Xiaokui’s ribbon — before her fight. Beat her first and the extra phase and its exclusive rewards are gone for that playthrough, which is exactly the kind of trap our missable side quests guide exists to prevent.

Phase 1: The Young Mistress

The opening phase teaches her two habits. She fires red swipe projectiles at range, then disappears and reappears with a red attack you must perfect dodge — the reappearance flash is your cue, not the swing. When she leaps into the air, prepare for a blue attack instead: parry it and Ghoststep in for free damage. The phase is a discipline check — she is testing whether you flinch at teleports. Don’t.

Phase 2: The Queen of Iron and Jade

Her second health bar renames her the Queen of Iron and Jade, and the tempo doubles. The signature string is a spiral red-and-blue glowing sword attack that she immediately follows with a red attack — perfect-dodge the follow-up; never assume the string is over. She also loves a red attack right after recovering Sha-Chi from a guard break: the tell is her lifting her arm into the air. The moment you break her guard, shorten your punish and keep your dodge finger ready.

Phase 3 (Ribbons Only): Iron Fiend & Jade Dancer

Collect all five ribbons and the fight does not end at two bars. Mu Xiaokui summons her two guardians — Jade Dancer, Young Mistress’s Guardian and Iron Fiend, Young Mistress’s Guardian — for a tandem finale. Two bosses, one arena, overlapping strings.

• Iron Fiend’s key tell: high knees and claps followed by a red attack. The clap rhythm is audible; dodge on the red flash, not the wind-up.
• Target priority: PCGamesN’s advice is to guard-break both at the same time where possible — synced staggers give you a real damage window — or, failing that, keep moving so they separate and farm whichever one overextends.
• Camera discipline: lock-on lies in duo fights. Toggle it off when they flank and play the spacing game until one commits.

Rewards: Fiend Saws and the Full Drop Table

The reward chain scales with your preparation:

• Standard clear: the Wild Oriole Sword. Note the fine print — Game8’s boss table lists it as Mu Xiaokui’s drop, while games.gg clarifies it is a separate pickup on the dock after the fight, not a Young Mistress quest hand-in. Either way, do not leave the arena without it.
• Ribbon-modified clear (phase 3): the Fiend Saws, Fist Fragment: Core, and Puppet No. 44’s Eye (PCGamesN, Beebom). The Fiend Saws are the headline — a second full weapon for a fight you were going to win anyway, which is why the ribbon detour is non-negotiable.

Common Mistakes to Avoid

• Fighting her before finishing Young Mistress. The single costliest error in the region — it permanently locks the Fiend Saws for that save.
• Greeding the guard break in phase two. Her post-break red attack exists to punish exactly that. Two hits, reset, repeat.
• Fighting the guardians as one blob. If Iron Fiend and Jade Dancer are both on screen and both aggressive, you are doing it wrong — move until they split.

Frequently Asked Questions

Is Mu Xiaokui’s third phase harder or just longer? Harder — two independent movesets at once is a genuine difficulty spike over phase two, and the Iron Fiend’s red follow-ups punish tunnel vision. It is also the only way to get the Fiend Saws.

Can I come back for the ribbons after beating her? No. The Young Mistress completion must happen before the fight. On a second run, use our New Game Plus guide route to sweep the ribbons early.

Do the ribbons carry over between playthroughs? The ribbons are per-playthrough collectibles; plan to re-collect all five on every run where you want the Fiend Saws drop.

Sources: polygon.com (ribbon locations, Young Mistress mechanics, Fiend Saws reward), pcgamesn.com (three-phase moveset, Queen of Iron and Jade, guardian tells, drop list), games.gg (ribbon-before-fight warning, Wild Oriole Sword dock pickup, Fist Fragment: Core), method.gg and beebom.com (ribbon locations cross-check, reward table) — launch-week guides, October 2026.