Guide
How the kit works
Start with Dance of Haftkarsvar, then perform three dance steps using Normal Attacks or the Skill. The third step decides the finish. Ending with the Skill creates a Whirling Water Wheel and a Tranquility Aura that follows the active character and applies Wet to nearby opponents. This is a useful choice when you want to switch to a teammate.
Ending with a Normal Attack instead produces a Luminous Illusion and gives Nilou Lunar Prayer. Her Normal Attacks become Sword Dance techniques, with another Luminous Illusion on the final hit. Dance-step damage is Hydro Elemental Skill damage, even when you use the Normal Attack button. Pirouette and Lunar Prayer end when Nilou leaves the field, and she cannot use Charged Attacks during either.
If the party contains only Hydro and Dendro characters, with at least one of each, the third step also activates Court of Dancing Petals. Golden Chalice's Bounty lasts 30 seconds. When affected characters are hit by Dendro attacks, all nearby characters gain 100 Elemental Mastery for 10 seconds. Bloom and Lunar-Bloom create Bountiful Cores instead of Dendro Cores; these cannot trigger Hyperbloom or Burgeon.
Use Dance of Abzendegi: Distant Dreams, Listening Spring when available for area Hydro damage. It marks opponents with Lingering Aeon, which deals another instance of Hydro damage after an interval.
Build and why
The first set choice is two pieces of Tenacity of the Millelith with two pieces of Vourukasha's Glow. Each pair gives 20% HP, helping Nilou's Max HP reach the range where Dreamy Dance of Aeons strengthens Bountiful Cores. For every 1,000 Max HP above 30,000, the bonus rises by 9%, up to 400%.
Four pieces of Deepwood Memories are an alternative: Skill or Burst hits lower the target's Dendro RES by 30% for 8 seconds. If another teammate already carries that set, four pieces of Instructor are worth considering for the 120 party Elemental Mastery granted for 8 seconds after its wearer triggers a reaction.
Use HP Percentage on the sands, goblet and circlet. In substats, look for HP Percentage first, then HP, Elemental Mastery and Energy Recharge. More Max HP supports Nilou's passive and her Hydro damage; Energy Recharge helps with using her Burst.
Key of Khaj-Nisut is the first weapon choice. It gives 20% HP, and Skill hits build stacks that grant Nilou Elemental Mastery based on her Max HP. At three stacks, nearby teammates also gain Elemental Mastery. The Dockhand's Assistant is a strong alternative: healing grants Symbols that a Skill or Burst consumes for Elemental Mastery and Energy. Serenity's Call increases Max HP after Nilou triggers a reaction; its bonus is larger with Ascendant Gleam.
Leveling priority
I'd level Dance of Haftkarsvar first for its Hydro damage, then Dance of Abzendegi: Distant Dreams, Listening Spring. Leave Dance of Samser (NA) until last if you mainly use the aura and switch out. The Bountiful Core bonus from Dreamy Dance of Aeons depends on Max HP, so raising talent levels is separate from building that bonus.
For ascension, collect Padisarah, Perpetual Caliber, Varunada Lazurite materials and the Fungal Spores, Luminescent Pollen and Crystalline Cyst Dust drops. Talents also need those drops, Praxis books, Tears of the Calamitous God and Mora. Maxing a talent requires a Crown of Insight.
Constellations worth it
The Starry Skies Their Flowers Rain is the standout upgrade. With Golden Chalice's Bounty active, dealing Hydro damage lowers the target's Hydro RES by 35% for 10 seconds. Bloom or Lunar-Bloom damage lowers its Dendro RES by 35% for the same duration. It requires Court of Dancing Petals.
Frostbreaker's Melody gives Nilou CRIT Rate and CRIT DMG based on Max HP, capped at 30% and 60%. It is more relevant if you also care about her personal damage. Dance of the Waning Moon is worth considering for its 6-second extension to Tranquility Aura; it also increases Luminous Illusion damage by 65%.
I'd skip C3 and C5 if the team-focused effects are your goal: they add levels to the Burst and Skill respectively. C4 gives Nilou 15 Energy when the third dance step hits and increases her Burst damage by 50% for 8 seconds, but it is also optional for the Bountiful Core playstyle.
Teams
Keep every party slot Hydro or Dendro, with at least one of each. Add Dendro teammates to react with Nilou's Hydro and a healer to keep the active character healthy. Nahida is a listed Dendro option; Lauma and Nefer are options for Lunar-Bloom teams. Sangonomiya Kokomi or Baizhu can cover healing while meeting the element restriction.
For example, Nilou, Nahida, Collei and Sangonomiya Kokomi meet the condition. Finish Nilou's Skill with the aura, then switch to teammates to continue the reaction setup. Columbina is another Hydro option for Lunar-Bloom, while Xingqiu can be considered for an off-field Hydro slot.
Nilou gives these teams the Bountiful Core conversion and an Elemental Mastery boost when the passive's Dendro-hit condition is met. Her aura lets the active character keep applying Wet without Nilou staying on field.
Common mistakes
Don't add a character of another element and expect Golden Chalice's Bounty to remain active. Breaking the Hydro and Dendro party condition cancels the effect. Also, don't plan on turning Bountiful Cores into Hyperbloom or Burgeon.
Don't stop Dance of Haftkarsvar before its third step: that step activates the party effect and determines whether you get the aura or the sword stance. If you want to keep attacking as Nilou, stay on field after the Normal Attack finish; switching removes Lunar Prayer.
Don't neglect Max HP while chasing Elemental Mastery. The HP-based Bountiful Core bonus only starts above 30,000 Max HP, and the suggested artifact main stats give you a direct way to raise it.
