Fae - the (Wind) Shaman
==============Theorycrafting===============
Fae's unspecialized stat spread and breath user characteristics narrow her possibilities for optimization, nonetheless, she can have a lot of different purposes in one's team.
Let's focus on 2 builds, a all-rounder build and a more specialized build, both trying to utilize Fae's high natural BST (so no TA, no L&D3, it's unoptimal on her!)
Build 1) Fae the furious chicken : "the classic KFC menu"
W: LightningBreath+
Sp: Iceberg
A: Fury 3
B: Quick Ripost 3
C: Threaten Res 3
This build1 works with most IVs set, as +Atk reach 52atk, +res empower Iceberg and kill most green mages on the 2nd hit (thx to QR), +def provides 4 extra def, mostly useful to tank braveAxe and braveBow. A boon in Hp isn't too valuable since she'll get doubled most of the time, so it's a good stat to bane. 28spd is a good value, enabling to double slow units, a bane would nullify this advantage to 0, and a boon wouldn't improve any significant matchup.
=============Theorycrafting 2.0===============
Build 2) Fae the shaman : "Earth, storm and fire, hear my call !" -the shaman
W: LightningBreath+
Sp: Best-3turn CD according to the A-skill (Moonbow if A is Windboost)
A: Elemental boost (Wind is best)
B: Quick ripost (Vantage if A is Windboost)
C: InfantryPulse or Honebuff (this build of Fae is self-sufficient, it's best to use her C skill to benefit the team).
recommended Seal: HP+3
Thanks to her built-in distant counter, Fae can draw the most out of the elemental boost (that provide the advantage of being effective on both Player and Ennemy Phases).
Concerning the IV sets, just like the build 1, she can benefit of most IVs set, but for the build 2, it's better to focus the elemental boost with the boon. This time, it's mostly effective to get a Spd boon since it enables Fae to benefit offensively and defensively from it. Moreover, it's not recommended to dump her HP since it's now part of the condition to utilize her A-skill. This way she can reach either 37spd (doesn't need QR anymore), 55atk (can OS some foes) or specialize on a tank side with 35def or 39res).
==> Basically, the Windboost version is the optimal skill variant for the Shaman build (build2), however it requires a Spn boon. Otherwise focus on the boon of your Fae to exploit it best with 3CD-special and QR.
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Question) Why don't you use TA on Fae ?
Answer) Using your A-skill slot to overkill Blue and get overkilled by Red isn't the smarter option. Get an elemental boost, some blue units will survive, some red units won't kill you, you'll kill more green. It's better.