Guide
How the kit works
Start by applying Hydro, Pyro, Cryo or Electro with a teammate. Switch to Heizou and use Fudou Style Martial Arts (NA) to attack: its Normal, Charged and Plunging Attacks all deal Anemo DMG. Charged Attacks consume Stamina. While Heizou is on the field, triggering Swirl or Stellar Swirl gives him one Declension stack, once every 0.1 seconds at most.
Use Windmuster Kick when you want its pull and damage. It creates an Arresting Windtunnel, and enemies hit while affected by one of those four elements can receive Windmuster Iris. The Iris explodes for damage of that element. Up to four enemies can be afflicted, and one enemy cannot have Irises of different elements at once.
Finish with Heartstopper Strike. Tapping releases a blow; holding charges it and builds Declension. At four stacks, Conviction makes the next strike stronger and gives it a larger area. A hit also grants the other party members 80 Elemental Mastery for 10 seconds.
Build and why
Use four pieces of Viridescent Venerer as the first choice. The set gives 15% Anemo DMG Bonus, increases Swirl DMG by 60% and lowers the opponent's RES to the element infused in Swirl by 40% for 10 seconds. That supports both Heizou's attacks and damage from teammates using that element.
Lavawalker is a conditional option against enemies affected by Pyro; Thundersoother does the same job against Electro-affected targets. For an attack-focused alternative, four pieces of Desert Pavilion Chronicle increase Normal Attack SPD and attack damage after a Charged Attack hits. Two pieces each of Viridescent Venerer and Golden Troupe are another option for Anemo DMG Bonus and Elemental Skill DMG.
For main stats, try ATK Percentage or Elemental Mastery on sands, Anemo DMG Bonus or Elemental Mastery on the goblet, and CRIT Rate, CRIT DMG or Elemental Mastery on the circlet. For substats, look for CRIT Rate and CRIT DMG first, followed by ATK Percentage, Elemental Mastery and Energy Recharge.
Skyward Atlas is the first weapon choice: it gives Elemental DMG Bonus and can trigger an extra attack on Normal Attack hits. Kagura's Verity boosts Elemental Skill DMG, while The Widsith gives one of three random buffs when Heizou takes the field. Sunny Morning Sleep-In is another option for Elemental Mastery; Mappa Mare is an option that gains Elemental DMG Bonus from reactions.
Leveling priority
A useful leveling order is Heartstopper Strike first, Fudou Style Martial Arts (NA) second and Windmuster Kick third. The Skill is the big blow you build stacks for, while Normal Attacks get frequent use when Heizou stays on the field. Level the Burst too if you use its damage regularly.
For maximum ascension, gather 420,000 Mora, 168 Onikabuto, 1 Vayuda Turquoise Sliver, 9 Vayuda Turquoise Fragment, 9 Vayuda Turquoise Chunk, 6 Vayuda Turquoise Gemstone and 46 Runic Fang. You also need 18 Treasure Hoarder Insignia, 30 Silver Raven Insignia and 36 Golden Raven Insignia.
Raising all talents to maximum needs a separate 4,957,500 Mora, 3 Crown of Insight, 9 Teachings of Transience, 63 Guide to Transience, 114 Philosophies of Transience and 18 The Meaning of Aeons. For those talents you also need 18 Treasure Hoarder Insignia, 66 Silver Raven Insignia and 93 Golden Raven Insignia.
Constellations worth it
Named Juvenile Casebook is the first upgrade to look at. After Heizou takes the field, it gives him one Declension stack and 15% Normal Attack SPD for 5 seconds. The effect can trigger once every 10 seconds, so it helps him start building toward his stronger strike.
Curious Casefiles is another notable upgrade for that strike. Each Declension stack adds 4% CRIT Rate to it, and Conviction adds 32% CRIT DMG. Esoteric Puzzle Book is also worth considering because it adds three levels to the Skill.
Investigative Collection improves the Burst's pull and extends it to 1 second. Tome of Lies returns Energy through Iris explosions, while Secret Archive adds three Burst levels. All three are optional: Heizou can use his stack-building and team support without them.
Teams
Give Heizou teammates who provide Hydro, Pyro, Cryo or Electro for Swirl and Windmuster Iris. Xingqiu and Yelan are Hydro options for off-field play; Fischl is an Electro option who can also work off-field. Their elements give Heizou targets for his Anemo attacks while he remains active.
For example, try Yelan, Fischl and Kuki Shinobu alongside Heizou. Kuki Shinobu is an Electro healer, so the team has healing as well as Hydro and Electro. Xingqiu can take the Hydro slot instead. Sangonomiya Kokomi is another Hydro healer to consider.
Bennett and Xiangling are Pyro options, while Faruzan is an Anemo teammate to consider. Zhongli can provide a shield if you prefer protection. Whatever the lineup, Heizou's Skill hit gives the other three members Elemental Mastery, not Heizou himself.
Common mistakes
Do not release Heartstopper Strike immediately every time without checking your stacks. Four Declension stacks give it Conviction, increasing both its power and area. You can build stacks through reactions while Heizou is on the field or by holding the Skill.
Do not expect Viridescent Venerer to lower every resistance at once. Its normal Swirl debuff targets the infused element, so pay attention to the element on your enemies. Likewise, Lavawalker and Thundersoother depend on targets being affected by their respective elements.
Finally, do not treat the party Elemental Mastery from a Skill hit as a buff for Heizou. If you want Elemental Mastery on him, choose it on his gear or weapon instead.
