Catherine

Weapon: Thunderbrand

Assist: Positional Assist / Flexible

Special: Galeforce

Passive A: Flashing Blade 4 / Swift Sparrow / Atk/Spd Push / Atk/Spd Solo 

Passive B: Wings of Mercy / Lull Spd/Def / Hit and Run

Passive C: Time’s Pulse / Joint Drive Spd / Spd Smoke / Def Smoke / Savage Blow / Flexible

Sacred Seal: Swift Sparrow / Quickened Pulse / Flashing Blade / Darting Blow 

• The sheer Player Phase potential of Thunderbrand alongside Catherine’s exemplary base offenses and infantry status makes her a clear candidate for a Galeforce set, geared specifically for Galeforce-centered strategies for Aether Raids Offense. Since the crux of her performance lies in her Speed (for consistent doubles and Flashing Blade), increasing this stat further with a +SPD IV is ideal; if unavailable, +ATK is a great alternative. She can take a Flaw in pretty much any other stat without issue thanks to Thunderbrand’s Desperation effect.
• The goal of this set (and its accompanying strategy) is to abuse Galeforce’s self-refreshing quality to quickly sweep through the majority of the enemy composition during the Player Phase. However, while Galeforce is certainly a powerful Special, it comes with the caveat of having a massive five-turn cooldown, though there are a few ways this can be worked around to maximize Catherine’s effectiveness. Regardless of the chosen route, though, Flashing Blade is non-negotiable. 
  • One can equip Flashing Blade 4 in the A slot and combine it with Time’s Pulse or the Quickened Pulse Sacred Seal; with Thunderbrand, this allows Catherine to immediately activate it on the second hit provided she can double. In a similar vein, Catherine can simply use the Flashing Blade seal and Time’s Pulse to benefit from the boost of standard offensive A slots instead. 
  • For the safest approach, one can attempt to have Catherine initially activate Galeforce on her first hit rather than the second, meaning that further reduction to its base cooldown will be required; the most achievable way will likely be getting Galeforce on a two-turn cooldown and using Flashing Blade. However, this isn’t too hard to achieve if so desired since besides Time’s Pulse and Quickened Pulse, she can also benefit from Infantry Pulse support. If available, the assistance of specific allies like Rafiel’s Groom Wings or Velouria’s Wolfpup Fang may prove especially useful.
• Should one choose to go with utilizing Flashing Blade as her seal, Catherine’s default Swift Sparrow 3 is a fantastic choice due to its massive offensive boost and synergy with this set’s offensive playstyle. Atk/Spd Push and Atk/Spd Solo may be potential considerations to squeeze out a bit more damage from Catherine, but they only offer one more point of Attack compared to Swift Sparrow so this typically won’t be worth it. 
• Thanks to Thunderbrand already securing her follow-up attack as long as she can outspeed, Catherine can forego equipping Null Follow-Up entirely in favor of Wings of Mercy. Its ability to teleport next to a weakened ally remains invaluable to easily close in on the enemy team without necessitating the use of outside support (such as from Smite), but one can keep Catherine’s default Lull Spd/Def to focus on damage instead. A movement based skill like Hit and Run may also be worth considering to quickly retreat after activating Galeforce.
• Catherine’s C slot -- like most other units -- is flexible. Besides Time’s Pulse, Joint Drive Skills are standout options to mutually buff herself and nearby allies in Galeforce chains; they are rather cost-intensive, though. More readily available alternatives include Smoke skills to improve the quality of Catherine’s subsequent matchups, though Savage Blow is an interesting option that works similarly but helps shut down Guard instead. 
• Lastly, if one finds that neither the Flashing Blade or Quickened Pulse seal is necessary, any available Sacred Seal that augments her offensive stats -- most notably Swift Sparrow, Death Blow, and Darting Blow for their Player Phase functionality -- should be taken. 

Weapon: Thunderbrand

Assist: Positional Assist / Flexible

Special: Glimmer / Moonbow / Ruptured Sky / Dragon Fang / Blazing Specials / Luna

Passive A: Swift Sparrow / Atk/Spd Push / Atk/Spd Solo / Life and Death

Passive B: Lull Spd/Def / Windsweep / Special Spiral

Passive C: Joint Drive Spd / Def Smoke / Spd Smoke / Flexible

Sacred Seal: Flashing Blade / Swift Sparrow / Death Blow / Darting Blow

• This build once again revolves around Catherine’s Player Phase strength, but showcases a generalist and damage-focused approach to her intended playstyle -- as opposed to the more specialized capabilities of a Galeforce setup. An Asset to either one of Catherine’s offensive stats is recommended here. 
• The primary consideration to make here lies in Catherine’s choice of Special. Those with a two-turn cooldown -- Moonbow, Glimmer, and Ruptured Sky -- are simple options that can be paired with the Flashing Blade seal for rapidfire activations on her second hit each time. Alternatively, one can add Special Spiral into the mix to activate Dragon Fang on her second hit each time or make use of AoE Specials once the initial chain is complete; this provides much higher damage, but conversely requires some setup beforehand to activate Special Spiral. If the Flashing Blade seal is unavailable, then Specials with three-turn cooldowns become Catherine’s best bet and will activate in every other round of combat. 
• Most standard offensive A slots work here. Catherine’s native Swift Sparrow is fantastic and will do perfectly fine, but one can equip her with Atk/Spd Push 4 or Atk/Spd Solo 4 to boost her damage a bit more; however, this is a very high investment recourse and the benefits are minimal, so doing so is only recommended if you really like her. If using an AoE Special, Life and Death is best to boost her visible stats, and Thunderbrand’s Desperation effect renders the cut to her defenses negligible.
• While Special Spiral is certainly a strong choice, Lull Spd/Def remains notable as well for its combination of enemy bonus negation and appreciable -3 in-combat debuff to her opponent’s Speed and Defense, making it a perfect accompaniment to this build’s focus on maximizing damage -- and fortunately enough, Catherine has it included right in her base kit. For a safer approach, Catherine can make surprisingly good use of Windsweep to negate enemy counterattacks while still being able to double thanks to Thunderbrand’s of Null Follow-Up, functioning as a Firesweep Sword but with a higher damage ceiling. 
• Her C slot options remain largely the same, with Joint Drive skills being excellent for their mutual buffing capacity and Smoke skills functioning especially well when provided refresher support. The same goes for her Sacred Seal since other than Flashing Blade, those that build upon her key stats are ideal; this includes Swift Sparrow, Death Blow, and Darting Blow.