Iron Fiend and Jade Dancer: Mu Xiaokui's third phase

The short answer

They are Mu Xiaokui’s third phase, not a boss you can walk up to.

You meet them at the end of the Village of Lu main story, in the same arena as Mu Xiaokui. If you did not finish the Young Mistress questline — all five ribbons collected before you take the elevator — the third phase never happens and you never see them at all. That is why the fight is missing from many playthroughs and why “I never fought them” is a common report.

Why they look like a separate boss

Three things make the confusion reasonable:

1. They have their own moveset. Jade Dancer fights on leg blades with ranged options; Iron Fiend is a heavier brawler. Neither reuses Mu Xiaokui’s animations.
2. They drop their own loot. Fiend Saws, Fist Fragment: Core and Puppet No. 44’s Eye come from the duo, not from her.
3. The health bar changes hands. She steps back and the duo takes the fight — visually identical to a new encounter starting.

None of that makes it a new encounter. There is no bell, no arena, no path. The only way in is through Mu Xiaokui.

Fighting them

Kill Iron Fiend first. He is easier to isolate — space out and he follows, which leaves a beat where Jade Dancer has not caught up and you get free hits. Then finish her alone. Killing either one halves the pressure; splitting damage between them does not.

The duo shares four red glint grabs:

The last one is a reaction test, not a read — treat it as the reason to keep your distance rather than a move you plan around.

They also perform a combined three-hit attack when close together, telegraphed by purple effects on Jade Dancer’s blade. Block the first two, parry the third. Both can throw their half of that combo solo, so do not assume the pair is required for it to come out.

Keep both in your field of view at all times. Getting trapped between them is the only way this phase goes wrong quickly.

The name problem: three names, one fight

The Iron Fever collision is not cosmetic. Stone Hand Iron Fever (拳痴·铁狂) is a separate main boss two chapters earlier, drops Iron Gauntlets, and has a real guide. A player sent looking for “Iron Fever” lands on the wrong boss and will believe what they find.

The boss’s own name drifts too: Mu Xiaokui is the standard spelling, but “Mi Xiaokui” appears in some weapon lists. Same fight, one letter apart.

Rewards

• Fiend Saws — dual-wield weapon; Fiend-Aura Erosion build-up, and Fiend Form makes attacks unblockable for 10s
• Fist Fragment: Core — Soul Temper
• Puppet No. 44’s Eye — story item
• Mu Xiaokui’s own clear gives the Wild Oriole Sword

The loot is why people care, and it is genuinely separate from hers — which is exactly why the phase gets listed as a boss.

Notes

• Two aggressive enemies with four grabs between them is the whole difficulty. Space management beats damage.
• The duo does not respawn separately. If you missed the ribbons, you missed the fight and the drops for that playthrough.
• Do not treat “separate page” as “separate entrance”. That assumption is what sends people looking for a door that does not exist.

Related

• Mu Xiaokui — the fight this phase belongs to, and the ribbon locations
• Heartless Remnants — the chapter hub
• All bosses