Firefly Build Guide, Abilities, and Best Teams - Honkai: Star Rail Guide - IGN (2024)

Honkai: Star Rail’s Firefly is one of the fastest DPS characters in the game. With the right Firefly build, you’ll turn this Stellaron Hunter mech into a brilliant Weakness-breaking DPS - with a little HP loss here and there.

From the best Light Cones and Relics to the best teams, these are our recommendations for the best Firefly build, plus everything else you might want to know about Honkai: Star Rail character Firefly.

How to Get Firefly

Firefly’s release date is June 19, at the start of Honkai: Star Rail version 2.3 phase 1. Firefly is a 5-star Fire character who follows the path of Destruction. As a 5-star character, she’ll be featured on her personal Character Event Warp banner. You can exchange one special star rail pass to get one “warp”; one chance to obtain Firefly. If you miss her banner, you’ll have to wait for a rerun banner in the future.

Firefly Stats

Firefly Abilities

• Basic Attack: Deals Fire DMG equal to 50% of SAM's ATK to a single target enemy.
• Enhanced Basic Attack: Restores HP by an amount equal to 20% of this unit's Max HP. Deals Fire DMG equal to 100% of SAM's ATK to a single target enemy.
• Skill: Consumes HP equal to 40% of this unit’s max HP and regenerates a fixed amount of Energy equal to 50% of this unit’s Max Energy. Deals Fire DMG equal to 100% of SAM's ATK to a single target enemy. If the current HP is not sufficient, reduces SAM's HP to 1 when using this Skill. Advances this unit's next Action by 25%.
• Enhanced Skill: Restores HP by an amount equal to 25% of this unit's Max HP. Applies Fire Weakness to a single target enemy, lasting for 2 turns. Deals Fire DMG equal to (0.2 × Break Effect + 100%) of SAM's ATK to this target. At the same time, deals Fire DMG equal to (0.1 × Break Effect + 50%) of SAM's ATK to adjacent targets. The Break Effect taken into the calculation is capped at 360%.
• Ultimate: Enters the Complete Combustion state, which advances this unit’s action by 100% and enables Enhanced Basic Attack and Enhanced Skill. While in Complete Combustion, increases SPD by 30, and when using the Enhanced Basic ATK or Enhanced Skill, increases this unit's Weakness Break efficiency by 50% and the Break DMG dealt by SAM by 10%, lasting until the current attack ends. A countdown timer for the Complete Combustion state appears on the Action Order. When the countdown timer’s turn starts, SAM exits the Complete Combustion state. The timer has a fixed SPD of 70. SAM cannot use the Ultimate while in Complete Combustion.
• Talent: The lower the HP, the less DMG received. When HP is 20% or lower, the DMG Reduction reaches its maximum effect, reducing up to 20%. During the Complete Combustion, the DMG Reduction remains at its maximum effect, and the Effect RES increases by 10%. If Energy is lower than 50% when the battle starts, regenerates Energy to 50%. Once Energy is regenerated to its maximum, dispels all debuffs on this unit.
• Technique: Leaps into the air and moves about freely for 5 seconds, which can be ended early by launching a plunging attack. When the duration ends, plunges and immediately attacks all enemies within a set area. At the start of each wave, applies a Fire Weakness to all enemies, lasting for 2 turns. Then, deals Fire DMG equal to 200% of SAM's ATK to all enemies.

Firefly’s kit makes her an excellent Weakness-breaking Fire DPS for your Honkai: Star Rail team, but beware that most of her damage comes from her enhanced Complete Combustion status. During Complete Combustion, Firefly gains a massive Speed boost, becomes even better at breaking enemy Weaknesses, and unlocks the more powerful versions of her Basic Attack and Skill. To activate Complete Combustion, you just need to trigger Firefly’s Ultimate.

During Complete Combustion, the best way to deal damage is through Firefly’s Enhanced Skill rather than the Enhanced Basic Attack, as the damage potential is much higher. Beware that the Enhanced Skill partly scales with Break Effect - something to keep in mind while working on your Firefly build. Due to Firefly’s high Speed, you will also need a lot of Skill Points, which is something to keep in mind while creating your Firefly team composition. If you run out of Skill Points, try to hit targets without Fire Weakness at least once with the Enhanced Skill before reverting to Enhanced Basic Attacks - this will place Fire Weakness on that target. Another great way to apply Fire Weakness is to start the battle with Firefly’s Technique, but this effect only lasts two turns.

As soon as the Complete Combustion status ends, your priority is to activate it again. To do so, use Firefly’s normal Skill twice, with each Skill use regenerating a fixed amount of 50% max Energy and advancing Firefly’s next action. Beware that this will cost 80% of Firefly’s max HP, but she’ll restore 25% HP upon triggering her Enhanced Skill. Furthermore, Firefly’s Talent greatly reduces incoming damage when she hits 20% HP, an effect that persists throughout Complete Combustion. She also gains increased Effect Resistance and is cleansed of debuffs whenever her Energy hits 100%, thus granting Firefly a surprisingly high survivability despite the Skill-based HP loss.

Firefly Traces

• Module A: Antilag Outburst (bonus ability Ascension 2): During the Complete Combustion, attacking enemies that have no Fire Weakness can also reduce their Toughness, with the effect being equivalent to 55% of the original Toughness Reduction from abilities.
• Module B: Autoreactive Armor (bonus ability Ascension 4): When SAM is in Complete Combustion with a Break Effect that is equal to or greater than 200%/360%, attacking a Weakness-Broken enemy target will convert the Toughness Reduction of this attack into 1 instance of 35%/50% Super Break DMG.
• Module Y: Core Overload (bonus ability Ascension 6): For every 10 points of SAM's ATK that exceeds 1800, increases this unit’s Break Effect by 0.8%.

The list above shows Firefly’s passive Trace abilities. As the Enhanced Skill during Complete Combustion only applies Fire Weakness to the direct target, not the adjacent targets, Module A is very useful when the adjacent targets aren’t inherently weak to Fire. Module B offers an amazing damage boost, but you must hit the required Break Effect in your Firefly build. Module Y allows you to build Break Effect through the Attack stat, which is also incredibly helpful. In short, you must unlock all Trace abilities to get the best Firefly build.

As for Firefly’s active abilities, prioritize her Ultimate upgrades, which improve the Speed and Break Damage bonuses during Complete Combustion. Next, upgrade the Skill for extra Energy Regeneration and Skill damage, followed by the Talent for better Damage Reduction and Effect Resistance during Complete Combustion. The Basic Attack upgrades aren’t important since Firefly hardly uses them.

Be sure to upgrade Firefly’s minor stat Traces for more Break Effect and Speed. The extra Effect Resistance is nice, but less important.

Firefly Eidolon Levels

Although you can get an amazing Firefly build at Eidolon Level 0, Eidolon Level 1 makes Firefly’s Skill Point management significantly easier as you will get ‘free’ Enhanced Skills during Complete Combustion - no longer should you need to build your Firefly team composition around Skill Point consumption. Eidolon Level 2 is also really strong as it grants additional turns during Complete Combustion - the goal is to trigger as many attacks as possible while the status is active, after all. Eidolon Level 6 simply offers a massive boost to Firefly’s damage output, while Eidolon Level 4 further improves survivability.

As always, this 5-star Honkai: Star Rail character comes with a signature Light Cone. You can get a perfectly fine Firefly build without this Light Cone, but if you lack a strong 5-star alternative, it’s often better to spend your Warps on the signature weapon instead of Eidolon Level 1.

Best Firefly Build

Here's an overview of the best Light Cones, Relics, Planar Ornaments, and stats for your Honkai: Star Rail Firefly build.

Best Firefly Light Cones

The best Light Cone for your Firefly build is her signature Light Cone, the 5-star Whereabouts Should Dreams Rest. As Firefly's Enhanced Skill attacks scale with Break Effect, the massive Break Effect increase granted by this Light Cone is very helpful. Firefly is focused on breaking Weaknesses, so any additional Break DMG is welcome.

The best alternative 5-star Light Cone for Firefly is On the Fall of an Aeon, which doesn’t provide a Break Effect boost but offers an amazing Attack bonus to make up for that. Fortunately, On the Fall of an Aeon is available in Herta’s Store, making it the best free-to-play Light Cone for your Firefly build.

If you can’t get any of the 5-stars yet, the best 4-star Light Cone for Firefly is Indelible Promise. It's the only Destruction Light Cone with a Break Effect stat, besides Whereabouts Should Dreams Rest. If you can get it to Ascension 5, it's almost as good as the signature Light Cone at Ascension 1.

Best Firefly Relics

The best Relic sets for Firefly should offer Break Effect, Speed, or (to a lesser extent) Attack - her most important stats. With many 2-piece Break Effect, Speed, and Attack Relics out there, you can get a great Firefly build by simply combining sets like Thief of Shooting Meteor, Watchmaker Master of Dream Machinations, Messenger Traversing Hackerspace, and even Musketeer of Wild Wheat.

That said, the best option is Iron Cavalry Against the Scourge, which greatly decreases enemy defense against Firefly’s attacks. Since Firefly should aim for a Break Effect above 250% anyway, the set effect works great for any Firefly build. Alternatively, you can use the full Thief of Shooting Meteor set, which doubles the Break Effect to 32%. Since Firefly relies on her Skill to replenish Energy, she doesn’t have much use for the Energy Regen offered by this set.

The best Planar Ornament set for Firefly is the Forge of the Kalpagni Lantern as it offers the highest possible Break Effect boost, plus a bit of extra Speed. Talia Kingdom of Banditry isn’t far behind, but it comes with a Speed requirement rather than a Speed boost, thus making Kalpagni the better option.

Best Stats

• Body: ATK%
• Feet: Speed
• Planar Sphere: ATK%
• Link Rope: Break Effect
• Sub stats: Speed, Break Effect, ATK%, Effect Resistance

Firefly needs Break Effect to improve her Break damage, specifically that of her Enhanced Skills. As she only deals good damage during her Ultimate's Complete Combustion state, she'll need to attack as often as possible while it's active - meaning she also requires a lot of Speed. The question is; how much Break Effect and Speed should you aim for?

Ideally, the best Firefly build would hit 360% Break Effect as her Enhanced Skill is capped at 360% Break Effect. This is also the Break Effect threshold required to unlock the full damage boost from the Module B: Autoreactive Armor Trace ability. Firefly gains 37.3% Break Effect from her minor Trace stats, 60% more if you use a fully upgraded Indelible Promise Light Cone or unupgraded signature Light Cone, around 56% Break Effect from Relic and Planar sets, and (if you manage to hit around 2400 Attack power) about 48% from the ‘Module Y: Core Overload’ Trace ability conversion. A fully upgraded 5-star Break Effect Relic would bring this to a rough total of 265% Break Effect. In other words, there’s no such thing as ‘too much’ Break Effect on your Firefly build - feel free to stack as much as you can in her Relic sub-stats.

As for Speed, Firefly needs at least 210 Speed to get four turns while Complete Combustion is active. Starting with her base 104 Speed, her Ultimate adds 60 Speed at Trace Level 10, her minor Trace stats add 5 Speed, and the ‘Forge of the Kalpagni Lantern’ Planar Ornament set adds 6% Speed. With Speed as a main stat on the Feet slot, this will bring you very close to the 210 threshold - just get a few additional Speed sub-stats and you’re done!

Finally, you may be wondering why Firefly, a DPS character, doesn't require Critical Rate or Critical Damage. The answer is that she scales better with Break Effect and Super Break - especially when wearing the full Iron Cavalry Against the Scourge Relic set. A great chunk of Firefly's damage comes from her Enhanced Skill during Complete Combustion, an attack that specifically scales with Break Effect. For similar reasons, you must choose ATK% over Fire Damage on the Planar Sphere slot; elemental damage doesn't improve Break Effect damage, but ATK% (thanks to Firefly's Module Y: Core Overload Trace ability) will.

Best Teams for Firefly

Unless you’ve unlocked Eidolon Level 1, Firefly is a highly Skill Point negative character; she must rely on her teammates to generate Skill Points with their basic Attacks. Choose support characters who can provide strong Break Effect buffs, Speed buffs, or Attack buffs (remember that her Attack stat also improves her Break effect) without being too reliant on their own Skills.

Firefly doesn’t benefit as much from Critical Rate, Critical Damage, and Fire Damage (see the ‘best stats’ section above for more details). As a result, many Harmony characters are still useful to her but not ideal: Bronya offers a handy Attack bonus and Advancing ability, but Firefly doesn’t need the Critical Damage. Asta can help you out if your Firefly build doesn’t have enough Speed, but you don’t need her Fire Damage buff.

Luckily, Firefly still has a perfect support character: Ruan Mei. This 5-star Harmony character not only improves her allies’ damage, but also their Weakness Break, Speed, and Resistance Penetration. On top of that, if Firefly breaks a Weakness, Ruan Mei deals additional Ice Break Damage against this target. Another brilliant support is the Harmony version of the Trailblazer. Using their Ultimate, Trailblazer improves Break Effect for all teammates - which will be converted to a Super Break bonus if a target already has their Weakness broken.

Although she can heal herself to some extent, your Firefly team still needs someone to keep them alive. Any healer will do, but Gallagher is especially great since he increases the Break Damage received by enemies during his Ultimate’s ‘Besotted’ status.

With that in mind, here are two examples of the best Firefly teams:

Best Firefly Team

In this Firefly team composition, Firefly is the main DPS, supported by Break Effect bonuses from all teammates. Harmony Trailblazer's goal is to keep their Ultimate's effect active (lasting for three turns) and use their Basic Attacks to generate Skill Points. Ruan Mei is also focused on keep her Ultimate active (two turns) as well as her Skill effect (three turns). She'll regenerate Skill Points between her Skill uses, making her slightly Skill Point positive. Ruan Mei doubles as a sub-DPS through her Ice Break Damage, which is automatically triggered if Firefly breaks a Weakness. Gallagher, too, is focused on keeping his Ultimate active. He will only use his Skill if an ally needs healing.

Firefly Free-To-Play Team

Firefly’s free-to-play team is quite similar to her best team; if you don’t have Ruan Mei, you can always go for another Harmony character or a Nihility enemy debuffer. Asta is a decent option, Tingyun isn’t bad either, but Pela would be best. Trailblazer is freely available to all players, but if you haven’t pulled 4-star Gallagher yet, you can go with starting character Natasha as your healer for the time being.

Need more characters to build the best Firefly teams? Take a look at our Honkai: Star Rail Warp guide for more info on the Warp system and the current character banners.