Guide
How the kit works
Before a fight, use Banner of Command to give all allies 15% ATK for the first 2 turns of the next battle. Once in combat, choose the ally who needs a turn and use Combat Redeployment. It removes one debuff, gives them an immediate action and increases their DMG by 66% for 1 turn. Bronya cannot give herself another immediate action with it.
Use The Belobog March to increase all allies' ATK by 55% for 2 turns. It also gives them CRIT DMG equal to 16% of Bronya's CRIT DMG plus 20% for the same duration. More CRIT DMG on Bronya therefore strengthens this buff.
When you need a Basic ATK instead, Windrider Bullet deals Wind DMG equal to 100% of Bronya's ATK to one enemy. Leading the Way then advances her next action by 30%. Command gives her Basic ATK 100% CRIT Rate; Battlefield grants the team 20% DEF for the first 2 turns, and Military Might increases allies' DMG by 10% while Bronya is on the field.
Build and why
For relics, start with 4-piece Sacerdos' Relived Ordeal. Its 2-piece bonus gives 6% SPD, and using Bronya's Skill on an ally gives that target 18% CRIT DMG for 2 turns, stacking up to twice. Messenger Traversing Hackerspace is an alternative: it gives 6% SPD and, after the wearer's Ultimate targets an ally, gives the team 12% SPD for 1 turn. That 4-piece effect cannot stack.
For the planar set, Broken Keel gives 10% Effect RES and grants all allies 10% CRIT DMG if Bronya reaches 30% Effect RES. Lushaka, the Sunken Seas is another option: it gives 5% Energy Regeneration Rate and 12% ATK to the first character in the lineup if Bronya is elsewhere in it.
Use CRIT DMG on the body, SPD on the feet and Energy Regeneration Rate on the rope. Choose HP Percentage or DEF Percentage on the sphere. For substats, look for CRIT DMG, then SPD, then Effect RES. CRIT DMG improves the Ultimate's buff, while SPD helps Bronya get turns to support the team.
A Grounded Ascent is the first Light Cone choice. Using Skill on an ally restores 6 Energy and gives that ally a stack of Hymn, worth 15% DMG for 3 turns, up to 3 stacks. It also recovers 1 Skill Point after every 2 qualifying uses. But the Battle Isn't Over gives Energy Regeneration Rate, can recover a Skill Point through the Ultimate and boosts the next other ally's DMG after Skill. Earthly Escapade adds CRIT DMG and grants teammates CRIT bonuses while Mask is active. Past and Future is a 4-star alternative that boosts the next other ally's DMG after Skill.
Leveling priority
Follow the game's order: Combat Redeployment, The Belobog March, Windrider Bullet, then Leading the Way. The Skill is your single-target action and damage tool, while the Ultimate buffs the whole team. Basic comes before Talent in this order even though Talent helps Bronya return to her next turn.
For maximum ascension, you need 308,000 Credit, 65 Storm Eye, and 15 each of Silvermane Badge, Silvermane Insignia and Silvermane Medal. Maxing all skills takes another 3,000,000 Credit, 8 Tracks of Destiny, 18 Harmonic Tune, 69 Ancestral Hymn, 139 Stellaris Symphony, 12 Guardian's Lament, 41 Silvermane Badge, 56 Silvermane Insignia and 58 Silvermane Medal.
Eidolons worth it
For Eidolons, I'd look at Hone Your Strength first. Using Skill has a 50% fixed chance to recover 1 Skill Point, with a 1-turn cooldown on the effect. It helps with the cost of supporting an ally, but it is not a guaranteed refund.
Piercing Rainbow is worth considering for its extra turn on the Skill's DMG boost. Quick March is another useful option: after the Skill target acts, they gain 30% SPD for 1 turn. Keep that timing in mind when arranging your team's turns.
You can leave Bombardment and Unstoppable for later if you are choosing which effects matter to you: they raise skill levels rather than adding a new action. Take by Surprise is situational, since another ally must use Basic ATK against an enemy with Wind Weakness; it can trigger once per turn.
Teams
Start with a damage dealer who wants another action. Blade, Jingliu, Boothill and Seele are examples named in guides. Bronya can advance whichever one you choose and give them the Skill's DMG bonus; her Ultimate also buffs the rest of the team.
A second buffer such as Ruan Mei or Tingyun is an option if the team can afford the Skill Points. Add a sustain character to keep the team alive: Bronya has a debuff removal and an opening DEF bonus, but no healing in her listed kit.
There is no fixed element requirement for Bronya's main support effects. Wind teammates are worth considering with gear that rewards matching damage types, but Blade is not required for her ordinary buffs.
Common mistakes
Do not use Combat Redeployment on Bronya expecting an immediate extra turn. Give it to an ally whose next action is useful, and pay attention to the 1-turn DMG buff. Try arranging turns so your damage dealer acts before Bronya, giving her a chance to bring them forward again.
Do not spend every Skill Point without considering what the damage dealer needs. Windrider Bullet is an option when you need to conserve points, and Leading the Way advances Bronya's next action after she uses it.
Do not build only CRIT DMG and ignore the rest of her gear. SPD helps her take turns, and Broken Keel needs 30% Effect RES to activate its team CRIT DMG bonus. If you use Lushaka, the Sunken Seas, check the lineup: Bronya must not be in the first slot for its ATK bonus.
