+Atk or +Spd Fir

k there are a number of ways to work with her lower atk. One is what you did, which is just go hard on it and aim for a naturally high atk stat, which is valid but in my opinion unnatural for her. That doesn't mean it's bad - it's a question of taste.

There's the big desperation special, which amoebasgonewild showed, 30 burst damage on that iceberg. Without flashing blade, even moonbow can do good work; you'll get 10-14 extra damage against opponents with high def, and if they don't have high def her regular atk will probably hurt enough.

The super-aggressive option is faux Ayra with wrath moonbow, so basically you're just spamming +10 moonbow the way Ayra spams RA using a slaying edge, and the damage is actually pretty comparable. RA on 40 spd hits for 16 damage (Ayra probably gets a little faster, so we're looking at maybe 18 damage?), and moonbow+10 is often in the 16-20 neighbourhood, higher against high-def opponents. Ayra does it better against physical attackers because she has good def; Fir does it better against manaketes because her res is better than Ayra's.

On all three of these strategies what I would recommend is figure out how fast you want her and how you're going to get there, and then you'll be able to see whether you want +atk or +spd.

About a week ago I raised the idea of spamming wrath noontime, which tends to restrict her to player phase (because your opponent needs to hit back for her to activate noontime twice in one round) just like moonbow-spamming. The difference, of course, is that noontime grants no extra damage on its own; it's just that Nameless Blade and wrath put +20 on it, so as long as your opponent doesn't have guard it's like your atk IV is 45. With 10 merges and swift sparrow (because she can only spam on player phase and recoil damage or bulk penalties don't make so much sense with noontime) you have the same damage as a galeforcer on 65 atk. Raven+10 on double L&D doesn't get that high without +atk himself, so I think you're fine to choose a boon other than atk for this setup. With swift sparrow and +10 she's at 44 spd, which is very respectable, and maybe spd ploy on top of it so maybe +spd isn't necessary (but of course it isn't bad). I actually think +def is very compelling with 10 merges because despite swift sparrow, Nameless Blade, and wrath, this is actually kind of a tank build, and 35 res I feel is enough for her ploys.

There's a suggestion of +res on her which I think is probably unnecessary at +10 but still an option to be considered. 35 res will probably hit the targets you need to hit, especially when it comes to spd ploy, and fury is still an option.

I'd lean more toward just Wrath. Given Fir has solid Res I lean more toward using a Ploy with her, I run Spd Ploy myself, over a Wave skill that's only active every other turn.

Oh forgot to change atk ploy for spd ploy.

And shes +res -hp. B4 i did have +spd but for me, as a support unit thatll always have spd ploy she doesnt need the +spd