Tsubasa

Weapon: Mirage Feather 

Assist: Positional Assist 

Special: Moonbow / Ruptured Sky 

Passive A: Atk/Spd Boosting A Slot 

Passive B: Flow Force / Flow Guard / Flow Skills 

Passive C: Spd/Def Hold (or Rein) / Atk/Def Rein / Atk/Spd Rein

Sacred Seal: Blade Session / Heavy Blade 

• If an ally has already acted, Mirage Feather grants Tsubasa +6 Atk/Spd and the ability to perform a follow-up attack before the enemy can counterattack during combat on initiation. As such, her sets naturally lean toward the objective of 2HKOing on Player Phase, with this set in particular maximizing her consistency (as opposed to the set below that emphasizes post-combat mobility).
• Since Tsubasa lacks any Special acceleration or additional Special charge, low-cooldown Specials such as Moonbow and Ruptured Sky work best, with the former being more accessible and stronger against enemies with high Def and the latter being better against Dragon and Beast enemies and units with much higher Atk than Def.
  • Heavy Blade in Tsubasa’s Sacred Seal allows her to activate her Special on her follow-up if no Special-slowing effects are active; however, actually passing the Heavy Blade check to receive the additional Special charge (Tsubasa’s in-combat Atk > the enemy’s in-combat Atk) can be difficult, so Blade Session can be used instead.
• Atk/Spd Boosting A slots such as Atk/Spd Catch, Atk/Spd Solo, Atk/Spd Push, and her native Blade Session maximize Tsubasa’s damage output and follow-up consistency, making them her strongest options.
• Neutralizing effects that prevent her follow-up, Tsubasa greatly appreciated the Flow family of B slots. While the secondary effects can be somewhat inconsequential, Flow Force is typically best to neutralize Tsubasa’s visible Atk/Spd debuffs, though Flow Guard can be strong for slowing enemy defensive Specials. 
• Spd/Def Hold and Spd/Def Rein are virtually identical; both inflict -4 Spd/Def on enemies during combat, but the latter does so on enemies within three spaces while the former only does so within two. If using Heavy Blade in Tsubasa’s Sacred Seal, then lowering the enemy’s Atk during combat maximizes her check consistency, so options such as Atk/Def Rein and Atk/Spd Rein are generally better.

Weapon: Mirage Feather 

Assist: Positional Assist

Special: Moonbow / Ruptured Sky 

Passive A: Atk/Spd Boosting A Slot

Passive B: S/D Near Trace

Passive C: Odd Tempest / Even Tempest / Spd/Def Hold (or Rein)

Sacred Seal: Blade Session

• Mirage Feather’s Armor-effectiveness and Tsubasa’s Flier status lands her some potential as a hit-and-run unit in Aether Raids Offense. Ideally, she 2HKOs the enemy’s frontliner (whether they be a Near Save Armored unit or not), then retreats with S/D Near Trace, which inflicts -3 Spd/Def on the enemy during combat and grants Tsubasa【Canto (Rem. +1)】after her first action of the current phase (she can move her remaining movement + 1 additional space). Note that this set is generally stronger on Astra:
  • Medeus, the best Dark Mythic at the time of writing, natively has Canto Control, which limits Tsubasa’s post-combat movement to only one space.
  • Because Tsubasa has to use S/D Near Trace in her B slot, she cannot run a Flow skill, which neutralizes effects that prevent her follow-up. Luckily, for players that have Naga, Tsubasa can gain a guaranteed follow-up from her C slot, Divine Fang+.
• Naturally, Tsubasa is only as strong as her KO capabilities, so her A and S slots are dedicated to maximizing her offenses. Any strong Atk/Spd Boosting A slot will do, with her native Blade Session being a relatively easy +9 Atk/Spd on initiation; stacking this with Blade Session in her Sacred Seal and Mirage Feather’s +6 Atk/Spd, she can gain up to +24 Atk/Spd during combat, significantly boosting her firepower.
• A Tempest C slot is important for Tsubasa; her average 2 movement fails to do her any favors for hit-and-run purposes (especially against Defense Keeps with high threat ranges), so gaining +1 movement on odd or even turns can provide her some much-needed mobility leverage. Spd/Def Hold and Rein can also serve as alternatives, increasing her damage and follow-up consistency via in-combat Spd/Def debuffs.