Eir

Weapon: Temari (+RES)

Assist: Smite / Flexible

Special: Moonbow / Iceberg / Luna

Passive A: Fort. Def/Res / Fury / Fortress Res

Passive B: Sabotage Skills / Disarm Trap / Link Skills / Chill Skills 

Passive C: Sparkling Boost / Ground Orders / Guidance / Drive Skills / Tactic Skills / Flexible

Sacred Seal: Phantom Res / Guidance / Aerobatics / Chill Skills / Drive Skills / Tactic Skills

• Given that the typical approach for Aether Raids Offense will usually leave Eir seeing battle rather infrequently, one can instead have the princess of death take a more supportive role and boost the performance of the team’s main carries. Although she can work perfectly fine with a neutral IV set, Eir benefits quite a bit from receiving +RES if available to improve the consistency of the mass debuffs she can apply via Temari (and potentially Sabotage skills). 
• Fort. Def/Res is Eir’s ideal choice of A slot if aiming to invest fully into stacking her Resistance to further augment her ability to land her debuffs, with the decrease to her Attack being entirely negligible since she likely won’t be engaging with opponents to begin with. If unavailable, Fortress Res is an excellent alternative or if wanting to preserve her combat ability while still boosting Eir’s visible Resistance (though to a lesser degree), Fury can be considered as well. 
• For her B slot, Eir has several readily available options depending on player preference:
  • Since Temari already applies a notable debuff to her foes’ Attack and Speed stats, one invest further into Eir’s debuffing capabilities either with a Sabotage skill (which shares a similar activation requirement to Temari) or a Chill; the choice between taking a Defense debuff or Resistance debuff, though, will depend on what type of damage the main carries specialize in.
  • Disarm Trap is a highly specialized, but interesting choice to safely test out enemy traps in Aether Raids and improve her allies positioning flexibility upon disabling them. However, since most traps are within close proximity of the actual opponents, using this skill does require a bit of finesse to fully utilize and will usually mean the assistance of a refresher or an outside ally.
  • Link skills are useful to apply strong bonuses to various stats at once, allowing her to wield buffing and debuffing utility simultaneously; these skills also pair well Smite to strengthen her intended ally while also allowing them to easily close in on the enemies. The preferred choice will once again depend on player preference, but having it provide at least a Resistance buff may be ideal given the context of AR Offense where magical damage is highly prominent. 
• Her exclusive Sparkling Boost can be plugged in to provide passive healing support to the rest of her teammates, though this may not be ideal if running her alongside allies who want to stay at low HP like standard Vantage nukes. If one finds that Sparkling Boost is unnecessary, movement-based support C slots (such as Guidance or Ground Orders) can be equipped, or simply any available selection of Tactic or Drive.
• The Phantom Res Sacred Seal fits excellently with this build’s intended purpose, assisting Eir in landing Temari’s debuff and potentially that of Sabotage skills if equipped; this may be of especially high value if using a neutral Eir, since she’ll need all the help she can get in boosting her base Resistance of 31. Any choice of Drive, Chill, or Tactic skill or Guidance/Aerobatics for movement support may also be considered.

Weapon: Lyfjaberg / Pumpkin-a-Box+ (+SPD) / Pumpkin-a-Box+

Assist: Reposition / Flexible

Special: Moonbow / Glimmer /Ruptured Sky

Passive A: Fury (3 or 4)

Passive B: Disarm Trap / Desperation / Escape Route

Passive C: Savage Blow / Spd Smoke / Atk Smoke

Sacred Seal: Savage Blow / Hardy Bearing / Spd Smoke / Atk Smoke

• Although this build once again assumes the context of Aether Raids Offense, it’s instead centered around Eir’s place in Galeforce-centric teams by becoming a beacon for other allies equipped with Wings of Mercy, with this strategy being more commonly known as “Eirforce.” A neutral IV set will once again work fine, though a boost to either one of her offensive stats is more than welcome. 
• The main gameplan here is relatively straightforward and centers around lowering Eir’s HP below 50% after two engagements (which means that the assistance of a refresher will be needed) to enable her allies to quickly close in on the enemies with little worry, and there’s a few ways this can be achieved. 
  • For low merge or the free neutral IV Eir, pairing her base Lyfjaberg with Fury 3 works excellently; combined, these two skills  will inflict 10 chip damage per combat for a total of a 20 HP loss after her two rounds of combat. This allows Eir to easily put herself in the Wings of Mercy threshold right up until she crosses over 40 HP.
  • If one’s Eir happens to cross this threshold (meaning 41+ HP) as a result of being highly merged, her bonus week, or some other factor, further skill investment will be required. The most readily available recourse is swapping out Fury 3 with Fury 4 for an additional 2 chip damage, bringing her HP cap to 48; this can also be done by replacing Lyfjaberg with Pumpkin-a-Box, but it is much more limited than Fury 4 and her PRF does carry other effects besides chip damage.
  • For maximum assurance, both Fury 4 and Pumpkin-a-Box can be taken to inflict 14 chip damage for a whopping 56 HP cap on Eir. However, for the majority of players, this will typically be unnecessary as Eir’s HP normally shouldn’t reach such an extent.
• Beyond the self-inflicted damage component of this set, there are other considerations to make. In particular, Disarm Trap is highly recommended to allow Eir to safely carry out her setup without worrying about trap placement disrupting this strategy -- while it is possible to use her without Disarm Trap, doing so involves much higher risk. If unavailable, B slot skills that operate at low HP (e.g. Desperation, Escape Route, etc.) are possible alternatives. 
• Using Savage Blow as her designated C and/or Sacred Seal slot is effective to knock down enemies below Guard’s HP threshold -- a skill detrimental to Galeforce strategies -- and allow her allies to potentially KO them in a single hit. Alternatively, Spd Smoke or Atk Smoke can be equipped if her paired teammates are dependent on skills like Flashing Blade or Heavy Blade to accelerate their Special charge. The Hardy Bearing seal also works well to work around potential Vantage units on a Defense map. 

Weapon: Lyfjaberg 

Assist: Reposition / Flexible

Special: Moonbow / Glimmer 

Passive A: Atk/Spd Solo / Atk/Res Solo / Swift Sparrow 

Passive B: Mystic Boost / Desperation

Passive C: Sparkling Boost / Smoke Skills / Flexible

Sacred Seal: Swift Sparrow / Atk/Def Solo / Sturdy Blow / Darting Blow / Death Blow

• Eir can also take a more generalist approach and focus on augmenting her offensive potential to serve as a consistent source of damage, performing especially well against mages. Once again, Eir will benefit notably from receiving a boost to one of her offensive stats, but a neutral IV set is still plenty workable if the free copy is the only available -- and to that end, she can function quite well with her base kit alone. 

• Moonbow will typically be Eir’s best option for her Special thanks to its low Special cooldown and effectiveness against bulky foes whom she would otherwise have difficulty in dealing with. Glimmer is also a great choice that possesses an equally low Special cooldown and scales well with more support/investment to her damage.

• Most standard offensive A slots are a natural fit to supplement Eir’s presence during the Player Phase; alongside her base Swift Sparrow, Atk/Spd Solo makes for a worthwhile consideration for its greater offensive boost and potential functionality in the Enemy Phase. Atk/Res Solo may also be a good selection to specialize the maiden further in her innately notable anti-magic capabilities.

• Her native Mystic Boost synergizes beautifully with Lyfjaberg to offset the chip damage it applies on her and further fortify her performance against dragonstone and stave wielders, safeguarding her from the majority of their damage output via its protection from Wrathful Staff and adaptive damage. For a more standard offensive choice with more widespread applicability, Desperation may be taken instead to freely strike opposing foes without having to worry about being killed in retaliation. 

• Her C slot is flexible and can be fit by whatever skill best suits her specific team composition. Besides her exclusive Sparkling Boost, Smoke skills (i.e. Atk Smoke or Spd Smoke since her weapon already applies the other two) are potential candidates if Eir is being provided with refresher support. 

• Lastly, any available seal that provides an improvement to her offensive stats is ideal for the purposes of this set; this includes Swift Sparrow, Atk/Def Solo, Sturdy Blow, Darting Blow, and Death Blow.