Firefly is an elite DPS whose kit revolves around sacrificing her own HP in exchange for massive Super Break DMG. Her Ultimate applies Fire Weakness, allowing her to use her Fire skills to easily trigger Weakness Break on a target, even if it isn’t naturally weak to Fire. This mechanic makes her an effective DPS against virtually any element type in Honkai: Star Rail.
How Firefly Works
Here’s a quick rundown of her skills:
| Type | Name | Description |
|---|---|---|
| Basic ATK | Order: Flare Propulsion | Fire DMG equal to 50–110% of ATK to one target. |
| Basic ATK | Fyrefly Type-IV: Pyrogenic Decimation | Heals an amount equal to 20% of Firefly’s Max HP and deals 100–220% of ATK to one target. |
| Skill | Order: Aerial Bombardment | Consumes 40% of Max HP, regenerates 50–62% of Max Energy, deals Fire DMG equal to 100–220% of ATK to one target. |
| Skill | Fyrefly Type-IV: Deathstar Overload | Heals 25% of Max HP, applies Fire Weakness to one target for 2 turns, deals Fire DMG equal to (0.2 × Break Effect + 100–220%) of ATK to one target and (0.1 × Break Effect + 50–110%) of ATK to adjacent targets. Break Effect used in calculation is capped at 360%. |
| Ultimate | Fyrefly Type-IV: Complete Combustion | Enters Complete Combustion state, increases SPD 30–66, increases Weakness Break Efficiency by 50%. Countdown timer at a fixed SPD of 70. |
| Trace | Module α: Antilag Outburst (Character Ascension 2) | Applies 55% Toughness Reduction on enemies with no Fire Weakness during Complete Combustion. |
| Trace | Module β: Autoreactive Armor (Character Ascension 4) | In Complete Combustion state with a Break Effect of 200–360%, attacking a Weakness-Broken target converts the Toughness Reduction into 35–50% Super Break DMG. |
| Trace | Module γ: Core Overload (Character Ascension 6) | Firefly gains 0.8% Break Effect for every 10 ATK stat over 1800. |
Firefly is a Break DPS who relies on quickly reducing Toughness to trigger Weakness Break, allowing her to demolish foes with Super Break DMG. Generally, here’s how she’s played:
- Use Fyrefly Type-IV: Deathstar Overload to apply Fire Weakness on enemies, then Weakness Break them with her Basic ATKs and skills.
- Use Order: Aerial Bombardment to regenerate half of her Energy. Do this twice and she has enough Energy to use her Ultimate.
- Use her Ultimate to enter Complete Combustion state. In Complete Combustion state, her attacks are converted into Super Break DMG.
Since she’s most effective during Complete Combustion, you want to deal as much of her damage during that period. This means laying down the appropriate groundwork to maximize her Super Break DMG with the appropriate buffs and debuffs. Here are the stats you need to focus on.
Stats to Prioritize
Firefly’s greatest strength is her ability to easily and reliably trigger Weakness Break on enemies, which allows her to deal Super Break DMG. Since Super Break DMG cannot CRIT, CRIT Rate and CRIT DMG are largely useless on her.
Break Effect
Break Effect is the most important stat on Firefly for two reasons:
- It increases Toughness Reduction on her attacks, which helps her trigger Weakness Break more easily; and
- it allows her to deal massive Super Break DMG.
Her Module β: Autoreactive Armor Trace (Character Ascension 4) makes it so when her Break Effect is 200–360%, Firefly deals 35–50% Super Break DMG to Weakness-Broken targets. You want to build Firefly and your team comp to allow for her to reach at least 360% Break Effect to get the full 50% Super Break DMG bonus. Any Break Effect over 360% is not used in this ability’s Super Break DMG bonus calculation but will still increase her base Super Break DMG.
ATK and ATK%
Firefly’s skills deal Fire DMG that scales based on her ATK stat, so you’ll want to have this stat as high as you can. Additionally, at Character Ascension 6, Firefly gains the Trace Module γ: Core Overload, which increases Break Effect by 0.8% for every ATK over 1800. In short, a higher ATK stat also gives her more Break DMG and improves her Super Break DMG potential.
Unfortunately, Firefly has abysmal base ATK, so she’ll need quite a bit of help getting to a decent ATK rating. With an ATK % body and orb, she can potentially hit 2,500 ATK, granting her 56% extra Break Effect—a decent contribution to the 360% Break Effect target we mentioned earlier.
SPD
As a Break DPS, more SPD means more turns to deal damage. On Firefly, this means more opportunities to deal Super Break DMG during her Ultimate.
Since her Ultimate gives her 60 bonus SPD, ideally, you want Firefly to have a base SPD of 150 in order to consistently hit the 210 SPD breakpoint during her Complete Combustion state. At 210 SPD, Firefly can attack four times before her Complete Combustion state comes to an end.
Recommended Builds
As your core DPS with self-sustaining heals, you want to build Firefly for maximum DMG output. As mentioned above, ATK%, SPD, and Break Effect are all priority stats, but any of these stats will also let her do her job more effectively:
- Break Effect buffs
- Super Break buffs
- ATK% buffs
- DEF Ignore/Shred debuffs
- Break Vulnerability debuffs
- Weakness Break Efficiency
SPD Boots > ATK% Boots
You can get ATK%, ATK, and Break Effect from support buffs and sub-stats; this isn’t true for SPD. So, build your Firefly and team comp for those three stats and boost her raw SPD with boots.
Recommended Team Comp
Part of what makes Firefly so powerful is that her ideal team comp is so F2P-friendly.
- Firefly (obviously)
- Harmony Trailblazer: Improves Firefly’s Super Break DMG potential. Ideally, she should have her 4-piece Watchmaker set to maximize the Break Effect bonus.
- Ruan Mei: Provides a Weakness Efficiency buff, SPD, Break Effect, Weakness Broken state extended, and All-Type RES PEN, which buffs Super Break DMG.
- Gallagher: Sustain character that scales with Break Effect.
In this comp, only Gallagher is truly swappable—everyone else is basically required to maximize Firefly’s potential. You also want SPD to be as high as possible on the Supports.
