Palla

~Flier Emblem Big Sister~

Palla has always excelled at covering for greens when so many common and/or good fliers are blue. Fury helps her tank overall, but Whitewing Blade brings a ton of damage potential against even neutral match-ups when considering Goad Fliers stacking. Will consider earlier than planned refine if powercreep of green armors gets out of hand.

Enemy/Player Phase hybrid Flier (Anti-Green Brave Attacker)

Palla's stats allow for her to be an effective All Around Unit, able to handle a variety of situations but not particularly shining at any. This build focuses primarily on her being an Enemy Phase defensive unit that can effortlessly switch between defense and offense, taking on a somewhat more supportive role for offensive flier based setups.
On the Enemy Phase, Palla is an Anti-Green unit due to the Gemstone effect of her weapon and Distant Counter allowing her her to cover both melee and ranged opponents. In conjunction with Fortify buffs and the +3 stat spread from her weapon, she easily reaches around 35+ on her def and res which isn't amazing but is plenty serviceable especially when combined with her good speed reaching around 43+ after hone buffs. This makes it so that she can easily take any green attack and a very good number of red opponents, killing them on the back swing with Quick Riposte.
On the Ally phase, the Triangle Attack refine enables Palla to effectively become a Brave Sword wielder so long as the requirement of 2 nearby flying allies can be met. While this can be tricky, a respectable 56+/43+ offensive spread (after hone buffs) brave weapon attack is the prize. The Gemstone effect means that even with this, Palla is pretty bad at attacking (and especially defending against) Blue units but can clean through a number of red units and nearly any green unit, a benefit which, as the number of powerful green armored units continues to grow, is highly sought after. Especially since this can even kill through effects that prevent follow-up, such as Wary Fighter.

Boon/Bane: Both Atk and Spd make for good Boons though Spd is the best for this build as it helps add to both defensive and offensive prowess but Atk highly benefits the Brave Weapons effect of the triangle refine and will better lend itself towards more aggressive strategies.
As for Banes either Hp, Def, and Res work with Hp likely being the best for this build as you'll want both your def and res but both -Def and -Res will work so long as caution is taken about letting Palla tank to many attacks from the respective damage types. However all three of these hurt bad due to the catch all nature of the build, but the new merge mechanic helps solve this issue and with Palla being such a common summon its not hard to get her to a +1 merge in order to get rid of the bane.

Weapon: While many dislike Gemstone weapons, the Triangle Attack refine on the Whitewing Blade is simply far to powerful to be passed up and is a big part of what makes Palla stand out among other red fliers as she is able to play the role of a Brave Sword wielder without sacrificing any of the Enemy Phase power.
If you are planning to use Palla among non-fliers then a Whitewing Blade (+Spd) or another weapon such as a Slaying Edge or Wo Dao can also work just fine, though you might be better off searching for a different sword unit instead, as much of this build's power will be lost in the process.

Assist: Reposition is the best by far, with fliers in particular being able to abuse it, especially in conjunction with other fliers.
This is however not required and anything can really fit in here depending on personal preference.

Special: Moonbow is generally the best option, able to add more damage and on a low cooldown.
While other options such as Bonfire or even more heavily invested skills such as Blue Flame or Aether can work just fine, they aren't really recommended as they don't particularly lend themselves to the build.

Passive A: Distant Counter is what allows for this particular setup to work, allowing for Palla to counter any Green unit melee or not.
This is however a very high investment skill but acts as a cornerstone to the purpose of this particular build. Palla can function perfectly well with skills such as Fury or more offensively focused sets with things like Swift Sparrow, Death Blow, and Line and Death (check other builds for more information on this sort of setup).

Passive B: Quick Riposte is the best option, as while Palla's speed is respectable, it's not enough to guarantee doubles against some of the faster units.
However, due to the Quick Riposte seal, this slot can be taken by other things if desired. Such as cheaper investment skills like Sword Breaker and R/G Tome Breaker or more niche utility such as Guard in order to combat special reliant enemies or Axe Breaker in order to guarantee kills on green units that prevent follow-ups.

Passive C: What this skill is doesn't matter much. As you will likely want to use a flier setup, some matter of flier buff is the best, just whatever best fits the team being used. If not using a flier team then same story, some sort of buff or utility that your setup utilizes will always do the trick.

Sacred Seal: I have HP/Res 2 set simply because I like the stats it provides and I think it helps to cover some of Palla's weak ends. What goes here changes heavily on what it is your team is calling for. If Palla is being used to take a lot of ranged attacks consider Distant Def, taking close range attacks consider Close Def, need for her to be more offensive due to green armor units use Quickened Pulse to rush out Moonbows on high Def targets (Works especially well due to the Brave effect) or +Atk/Spd to pad out her offensive spread, having trouble with archers consider Iote's Shield.
The options are vast and can change based on what seals are in use and what your current team is calling for. Should you opt for a different B skill than Quick Ripose, I would heavily recommend taking it here as it makes her enemy phase far more reliable.

With Whitewing Blade, Palla becomes an excellent offensive Red Flier, arguably better than L!Ryoma, the previous reigning champion.

The Triangle Attack effect on the Whitewing Blade is very powerful. However, the Whitewing Blade has one problem: Triangle Adept. While not a bad skill in its own right, it does not allow Palla to effectively deal with Blue foes. To counteract this, we run Cancel Affinity to disable its effect. If you want to use her as a Surtr counter or something, I recommend running Axebreaker to insure a quad attack regardless of Wary Fighter, though this is not necessary.

Moonbow and Heavy Blade allows Palla to activate Moonbow on her second hit. With a +Atk IV at +10 and with all of her skills active, Palla reaches a ridiculous Attack of 62, a value that will allow her to take down a vast majority of the cast. I would recommend running Goad Fliers on her allies so that she can easily take down more. Camilla is also a great ally for her, giving her an extra 3 Attack and Speed. All of these buffs give Palla 77 attack, enough to activate Heavy Blade in almost every fight.

I chose Atk/Spd Bond over the superior Death Blow 4 because, alongside giving her only 3 less attack, it allows her to hit a speed of 43 without buffs. While this value won't allow her to double everyone, it gives her enough speed to double important enemies such as Laevatein and Zelgius. Alongside this, it will be consistently activated because you will always want to have allies next to her.

Her Assist and C slots are flexible. Odd Attack Wave allows her to win against anyone at +10 with full buffs and their base kit, but it is inconsistent in the long run.

We take a -Res nature because her Res is pretty bad at base, but even that gets to 30 at +10 with her weapon effect active.

Flying Fortress Palla for a merge project.

+Spd nature, coupled with a Spd refined weapon, brings her to 41 spd at +10. With team support, she's very hard to double. -Res is preferred to -HP to conserve her physical bulk and ability to use skills like Guard or Quick Riposte for longer periods of time.

Double Close Def and Safeguard makes her into a melee wall, even against non-blue dragons. At +10, she has 51/39 defenses when a melee enemy initiates, and that's ignoring team support. Coupled with her 51 HP that's 102/90 bulk on the enemy phase, and with her high speed, she's hard to take down in one round of combat.
Guard is here to prevent the enemy from activating their specials, increasing Palla's longevity. If she isn't provided with any Spd support from the team, Quick Riposte can also be used to ensure she doubles.
Atk Smoke helps her take on multiple enemies in a single turn. It can be replaced for team support skills like her native Goad Fliers or even Panic Ploy.
Safeguard can be replaced for a Slaying Edge, allowing Palla to activate a Bonfire of at least 22 damage every round of combat, assuming she doubles.
Bonfire can also be replaced for Ignis for at least 40 damage but fliers' lack of skills like Steady Breath to accelerate their special countdown charges (oustide of Heavy Blade, but Palla doesn't have the Atk stat for that) means she won't proc it very often.

Palla doesn't have a very impressive player phase, however. She struggles dealing significant damage, and her Bonfire damage is unipressive without the close defenses+Safeguard factoring in. Other weaknesses of this set include weakness to archers and obvious lack of Distant Counter.
Palla appreciates L!Robin as a teammate due to Robin's skill Dragonskin which allows her to tank Archers and ranged magic threats Palla cannot handle. Robin's blessing also gives +3 Spd to Palla during the Earth season, boosting Palla's ability not to get doubled even further.

Palla is mainly used to pick off enemy units one at a time. She can get in, deal so damage, and then get out.

Wo Dao, due to its effect, is the best option for any Palla Build. With a Might as strong as any other weapon after a Refine, it can secure kills much better when paired with Moonbow than any other weapon.

Since she has a decent Def stat for a Flier, Palla can utilize Brazen Atk/Spd very well. It will increase her strength to 52/45 once in its range, which can make or break a battle.

Due to her high speed, Palla can use Desperation effectively. Once paired with Brazen Atk/Spd, she can double units like there is no tomorrow.

Due to a good HP stat, Palla can use Panic Ploy well, due to the abundance of low HP glass cannons in Arena.

Attack +3 again increases Palla’s strength to 55/45 after Brazen, which can disintegrate many units, including armor units.