Honkai: Star RailFireflyBest build, teams and other guides

Firefly is a remarkable Break-focused unit. She can regain her Ultimate extremely fast with her Skill's percentage restore and has a natural 25% Action Advance when using said Skill, though it also consumes HP to use. With her Ultimate, she immediately Advances her turn by 100% and gains vastly increased SPD, Damage Reduction, Effect RES, and Weakness Break Efficiency when attacking enemies. During her Ultimate, she will also be able to heal herself when using her Enhanced attacks, and she will implant a Fire Weakness onto the main target of her Enhanced Skill. She has a very synergistic kit that lends itself to having many ways of improving over time.

Ah, finally, everyone's favourite Kamen Rider, Gundam, Orbital Frame, Samfly soon will become playable! There's a frightening lot about her that's great and a little about her that's somewhat rigid for now, but all of this culminates in one of the highest-ceiling characters we've gotten so far. To leave it at that wouldn't be telling the whole story, but make no mistake, Firefly has no trouble wiping the floor with pretty much everything that breathes.

Her kit is very interlinked, so we'll start with Firefly's Ultimate. It has a colossal cost of 240 Energy, though this is not as limiting as it may initially seem. Upon using the Ultimate, Firefly enters the Complete Combustion state. She gets a 100% Action Advance, meaning it is now her turn, and she gains up to 60 SPD. She gains access to an Enhanced Basic ATK and Enhanced Skill, and the Weakness Break Efficiency of these Enhanced attacks is increased by 50% and the Break DMG received by enemies is increased by up to 20%.

This Ultimate state gets a separate countdown timer in the Action Order, much like Robin's Ultimate, with a fixed SPD of 70. The Ultimate may not be recast before it expires, but if you defeat all enemies within a cycle in Memory of Chaos, you can extend the effects of the Ultimate as the fixed SPD countdown gets thrown back down the Action Order. By default, this allows SAM to perform 3 Enhanced attacks per Ultimate usage.

Her Talent provides her with DMG Reduction based on how low her health is, capping out when her health is at or below 20% Max HP and giving her up to a 40% DMG Reduction. However, during her Ultimate she will always have the maximum amount, and additionally gain 30% Effect RES on top. When her Energy reaches 100% in combat, all of her debuffs will be dispelled, meaning she will almost never be subject to pesky stat-reducing debuffs when she goes to destroy enemies in her Ultimate. This Talent will also ensure Firefly starts every fight with at least 50% Max Energy if she is below 50% when combat starts.

Firefly's Skill consumes 40% Max HP to deal up to 200% ATK to a single target, and recovers up to 60% Max Energy on use. If there's not enough HP, the HP is set to 1. Using this Skill will also Action Advance Firefly by 25%. This is why the aforementioned 240 Energy cost of the Ultimate is less relevant, as it will always take at most 2 Skill uses to regain Firefly's Ultimate, and with the Action Advance she can further expedite the process of getting back into her Complete Combustion state.

While she is in the Complete Combustion state, this Skill is Enhanced. It will now restore 25% Max HP on use, and will apply Fire Weakness to the primary target. It becomes a Blast AoE, dealing... Oh, huh. (0.2 x Break Effect + 200% ATK) to the primary target, and half of this to adjacent targets. The Break Effect taken into account for this attack caps at 360%.

Okay, this is the point at which I have to remind you that Firefly is an entirely Break-focused unit with no inherent CRIT scaling in her kit - you’re hitting for peanuts before an enemy is Broken. Samfly is designed to take advantage of the Weakness Broken state by dealing Super Break DMG, stacking a lot of SPD and Break Effect to maximize the damage you can deal and speed up the process of Breaking foes again. The immense bonuses she gets from her kit make her expertly suited for the task of abusing Broken foes, especially with the guaranteed Fire Implant on her Enhanced Skill, as well as the ATK conversion Bonus Trace.

We'll skip ahead to her Bonus Traces since it's relevant to illustrate her Break focus. Her A2 will allow SAM in Complete Combustion to deal 55% of the original Toughness damage to enemies that are not weak to Fire. This is not always useful since her Enhanced Skill Implants Fire Weakness, but it will affect the adjacent that don't get Implanted. The A4 states that while SAM is in the Complete Combustion state with 200%/360% Break Effect or more, attacking a Broken enemy will convert the Toughness reducing damage of this into a single instance of 35%/50% Super Break DMG. The A6 also has a stat conversion, turning every 10 points of ATK beyond 1800 into an extra 0.8% Break Effect.

So what does all this mean? Samfly is designed to take advantage of the Weakness Broken state by dealing Super Break DMG, stacking a lot of SPD and Break Effect to maximize the damage you can deal and speed up the process of Breaking foes again. The immense bonuses she gets from her kit make her expertly suited for the task of abusing Broken foes, especially with the guaranteed Fire Implant on her Enhanced Skill, as well as the ATK conversion Bonus Trace.

Here's the primary issue: Firefly's intrinsic Super Break is not that strong on its own. It sounds like it'd be quite strong but it's surprisingly weaker than her kit would imply. This is exacerbated by the completely fake damage her upfront multipliers give because, as mentioned before, she is an entirely Break-focused unit. She can very quickly and easily get enemies Broken, but she appreciates some assistance to continue the decimation after they're already Broken.

This means Firefly needs her emotional support raccoon, the Harmony Trailblazer. The immense amount of Break Effect that the Harmony Trailblazer grants alongside the Super Break provided by the Backup Dancer effect is exactly what Firefly needs to destroy enemies. The Super Break from both characters are two separate instances, so it results in a lot of damage after enemies are Broken. The Trailblazer's A6 also results in enemies getting delayed further after allies Break them, giving even more time to deal Super Break.

This is the only truly non-negotiable teammate for Firefly. The difference with and without Harmony MC is staggering, like, Firefly is not the same character without the Trailblazer by her side. To better illustrate this, Firefly’s Super Break is at 50%, while Harmony MC’s Super Break can be as high as 160%. It’s genuinely not close.

The upside is that everyone has the Harmony Trailblazer, so as far as being tied to a single support character goes, it could be much worse. They provide everything that Firefly wants and also contributes a significant amount of both Toughness damage and Super Break damage of their own.

In terms of sustain characters, it's also fairly cut and dry as it's just shrimply the best to bring Gallagher, for all the usual reasons: great sustain, very sp positive, and massive Toughness damage and bonus team Break damage. That last point is particularly relevant as Firefly is constantly Implanting Fire Weakness onto enemies, meaning Gallagher is also able to exert his full power at every turn. Gallagher does a lot of the heavy lifting in terms of regaining SP for Firefly, so it’s a big difference if you don’t have him.

You do have other options if Gallagher is occupied by another team or if you don't have him; the usual suite of premium sustains are always good, though due to Firefly's rather exorbitant SP spending, I'd recommend going for the fully SP positive sustain options. Lingsha is an upgrade to Gallagher, but only if your Firefly is E1 or higher - sadly at E0, Firefly is a Skill Point black hole and Lingsha will underperform compared to Gallagher.

For the last teammate slot, you do have options, but the obvious best choice is Ruan Mei. She is the best choice for this slot. Granting Firefly even more SPD, even more Weakness Break Efficiency, and RES PEN on top of all of that results in the team dishing out frankly absurd damage. Thanatoplum keeps enemies Broken for longer as well, and Weakness Break Efficiency acts as a multiplier on the damage of Super Break. Do note that Ruan Mei's and Firefly's Weakness Break Efficiency bonuses are additive with each other, but it's still extremely potent.

To give some context on the other options for this team slot, there are two other issues that Firefly has at base; the first is that she is extraordinarily fast with additional Action Advance to boot, making her consume substantially more SP than you may be expecting. Ruan Mei is not massively SP-positive, but the damage she provides makes it worth the extra hassle. You really have to carefully consider your SP economy, or you'll end up in a terrible spot without being able to continue your offence right as the enemy gets Broken, leading to a colossal loss of damage.

The second issue is that Firefly's Weakness Implant may make an enemy weak to Fire, but it does not apply the associated RES Down that comes with natural Elemental Weaknesses, meaning if an enemy is highly resistant to Fire, even if they're now taking Toughness damage, they'll still end up reducing Firefly's Super Break DMG once they're Broken; if an enemy has 60% RES to Fire, Implanting Fire Weakness with Firefly will not really do much to alleviate the issue, but Ruan Mei’s RES PEN can greatly assist with this.

To that end, if you do not have Ruan Mei available for the team, the next best choices are the classic debuffing supports of Pela and Silver Wolf. They’re both definitively worse than Ruan Mei, but they are passable alternatives. Both of them provide massive DEF Shred which vastly improves the damage of Super Break and can also alleviate the natural Resistances of an enemy if you are trying to use Firefly to brute force content, and both of them are relatively SP positive, allowing Firefly to stay on the offensive for much longer. In addition to that, since they debuff the enemies, it's not possible for SAM to outspeed the benefits these actions provide.

Some supports that don't really work as well would be Bronya and Asta, primarily because they're too SP hungry and their buffs disappear in a flash on SAM. To illustrate this point, there is a certain SPD breakpoint that SAM can reach to act an extra time in the Complete Combustion state, and it's around 210 SPD. That's... quite a ridiculous amount of SPD, and it does need a certain amount of investment to reach, but with that kind of frequency of attacking, any buffs applied directly to SAM will vanish before you know it, making it largely redundant to even try it. If you are a completely, absolutely new player without access to anything else, Asta may be used, but please endeavour to replace her with at least Pela as soon as you can, it is night and day.

There aren't that many dedicated Break supports at the moment, so the optimal setup for Firefly at this point in time is extremely specific and inflexible, with the only team slot that does have some flexibility being limited to 3 of the most highly coveted support characters in the game. It is not that easy to substitute characters beyond that point, and results in a steep drop off in damage and ease of play. That said, Firefly's kit is so overloaded with fantastic free effects that any new characters that can facilitate this Super Break playstyle will mesh extremely well with what SAM can do.

I've left Eidolons for last, because as usual I don't think they're necessary, but Firefly in particular has a very appealing set for people looking to vertically invest. E1 is the one to go for; when using the Enhanced Skill, the DMG dealt ignores 15% DEF, and more importantly, the Enhanced Skill will no longer consume Skill Points. This alone opens up the possibility for far more SP-heavy support characters like Bronya, and makes it that much easier to reach 100% DEF reduction with the right setups. E2 is also extremely impressive, making it so that whenever an enemy is defeated or Broken while under Complete Combustion, SAM gets an Extra Turn, with a 1-turn cooldown between triggering this effect. Basically, you get Seele's Resurgence but without the need to worry about SP (since you're already past E1 at this stage).

E3, E4, and E5 are largely filler on the way to E6 (though E4's 50% Effect RES is quite nice). E6 grants SAM 20% Fire RES PEN under Complete Combustion, and provides an additional 50% Weakness Break Efficiency when using either Enhanced attack, for a new total of 100% Weakness Break Efficiency, literally doubling the Toughness damage of the attacks. This is arguably not as impressive as the likes of Acheron E6 or Boothill E6, but factoring in what you got along the way, SAM is basically completely unstoppable at this point.

Light Cone options are also surprisingly cut and dry this time around, as there's only really one choice for you if you're not going for her signature, and that's On the Fall of an Aeon. It just gives her everything that she needs and is completely free for everyone, the only downside is that it's hotly contested so you may need to yoink it from another Destruction character if you want to have the best on Firefly.

The conversation surrounding the choice between E1 and S1 is always tricky because it's really ultimately up to the individual player. Both choices are very good with both providing a great amount of benefit to Firefly. S1 is easier to go for because the odds of pulling it are higher, but for Firefly, E1 is probably the stronger choice overall albeit more expensive on average. By no means do you need either, and we're not evaluating her with these in consideration, it's just for the devoted few. As always 'make a choice you know you won't regret' etc etc, you know the drill by now.

Actually, if you don’t already have Ruan Mei, get Ruan Mei. She’s getting rerun with Firefly so do yourself a favour, like actually, real.

With Firefly's release, we've had back to back to back-banger characters, able to tackle pretty much everything in the game without reprieve. This is one of the best characters to go for and have on hand because, like with Acheron, Feixiao and Boothill, it's borderline impossible to stop Firefly from eviscerating everything. Enemy without Fire Weakness? No problem at all, here's a Fire Weakness. Enemy with really high Fire RES? Ruan Mei sends her regards. Multiple Break bars and shared HP pools? Firefly missed the part where that's her problem.

It would take enemies permanently locking their Toughness bars or having full immunity to Fire for Firefly to be completely put out of commission, and that's unlikely to happen because it'd affect almost every other DPS character as well. This coupled with the fact that Firefly's kit is extremely easy to scale with future characters, and this may well be one of the best characters to invest in in the entire game.

She truly will set the seas ablaze.