Guide
How the kit works
Bring Aalto in with Feint Shot for Aero DMG, then use Shift Trick. It creates Mist and a Mist Avatar that taunts nearby targets. The avatar inherits a portion of Aalto's HP and generates 6 Mist Bullets, which count as Resonance Skill DMG.
Fire Basic Attacks through Mist and hit a target to recover Mist Drops for Misty Cover. Mid-air Attacks work too. Aalto can hold 6 Drops. The fourth shot of Half Truths also creates Mist that lasts 1.5 seconds.
Pass through Mist or the Gate of Quandary to enter Mistcloak Dash. It increases movement speed and consumes Drops continuously, generating one Mist Bullet per Drop. Mid-game Break also recovers STA during the dash.
Use Flower in the Mist to deal Aero DMG and place the gate for 10 seconds. Shoot bullets through it for increased damage. Perfect Performance guarantees a critical Heavy Attack once every 30 seconds.
Finish by switching to your Aero damage dealer with Dissolving Mist. Its 23% Aero DMG Amplification lasts 14 seconds, or until that incoming Resonator switches out.
Build and why
For Aalto's own damage, consider Sierra Gale first: its two-piece effect gives 10% Aero DMG. Moonlit Clouds is the alternative for Energy Regen, with 10% from two pieces. The game recommends five pieces of Moonlit Clouds, though its five-piece effect is not listed here.
The Last Dance is the first weapon choice. It gives 12% ATK, and using Intro or Liberation grants 48% Resonance Skill DMG Bonus for 5 seconds. That bonus suits the Mist Bullets from Aalto's Skill.
Phasic Homogenizer is another damage option: it gives 12% ATK and, after a teammate uses Tune Break, grants the wielder 20% All-Attribute DMG Bonus for 14 seconds. Static Mist instead gives 12.8% Energy Regen and grants the incoming Resonator 10% ATK for 14 seconds after Aalto's Outro.
Among 4-star options, Undying Flame gives 20% Resonance Skill DMG Bonus for 15 seconds after Intro. Novaburst rewards dashes or dodges with ATK, while Cadenza restores 8 Concerto Energy on Skill, once every 20 seconds.
Energy Regen is worth considering if you want the gate available more often. Aero DMG suits his attacks; Crit. Rate is another option, though the guaranteed critical Heavy Attack does not need it when the passive is ready.
Leveling priority
A suggested order is Skill first, then Forte and Liberation. Skill creates the avatar and Mist Bullets, while Forte is tied to the Drops you spend in the dash. Liberation adds the gate to your rotation. Level Basic Attack and Intro afterward; this order is a suggestion rather than a guide-backed ranking.
For maximum ascension, you need 170,000 Shell Credit, 4 LF Howler Core, 12 MF Howler Core, 12 HF Howler Core, 4 FF Howler Core, 46 Roaring Rock Fist and 60 Wintry Bell.
For all skills, you need 2,030,000 Shell Credit, 25 LF Howler Core, 28 MF Howler Core, 40 HF Howler Core, 57 FF Howler Core, 26 Monument Bell, 25 Impure Phlogiston, 28 Extracted Phlogiston, 55 Refined Phlogiston and 67 Flawless Phlogiston.
Resonance Chain nodes worth it
For Aalto's damage, Hazey Transition (sequence 3) is a suggested priority: Basic or Mid-air Attacks passing through Mist generate two extra bullets, each dealing 50% of the original attack's damage.
Trickster's Opening Show (sequence 1) is useful to consider for more frequent Skill use, reducing its cooldown by 4 seconds. Blake Bloom for Finale (sequence 4) increases Resonance Skill Mist Bullet damage by 30% and reduces damage Aalto takes during Mistcloak Dash by 30%.
Broker's Secrets (sequence 6) is another option if you use Heavy Attacks through the gate: Liberation increases Crit. Rate by 8%, and a Heavy Attack passing through the gate deals 50% more damage. For an Outro-focused Aalto, stopping at sequence 1 and leaving the later upgrades is reasonable. The 23% Aero amplification is already in his default kit.
Teams
Put an Aero damage dealer immediately after Aalto so they receive his Outro. Jiyan and Rover: Aero are both named as teammates in the guides; Qingxiao is another Aero option named there.
A third slot can cover sustain. Verina and Baizhi are also named by the guides as teammates. With Static Mist, the character entering after Aalto receives its ATK increase alongside the Aero amplification.
Common mistakes
Do not dash through Mist before building Drops if you want Mist Bullets from the dash. Your shots must pass through Mist and hit a target to recover Drops, and the cap is 6.
Do not fire away from the gate and expect its bullet damage increase. Place it ahead of Aalto and aim through it; it lasts 10 seconds.
Do not switch away from the recipient early if you still need Aalto's Aero amplification. Also, do not assume every Heavy Attack is guaranteed to crit: the passive triggers once every 30 seconds.
