Scathacha provides a potent mix of supportive buffs, support skills that further buff her and her allies when these buffs are present and significant personal damage on an Enmity basis. Since Enmity builds are easily available in Wind grids, this makes her pretty easy to use right away and her skills can even enable Enmity right at the start of the fight for the entire team.
How to Play
Deirdre's AuraAll allies gain 30% Wind ATK UpWind ATK is boosted Strength: 30%Duration: 3 turns. At level 90: 30% Wind ATK UpWind ATK is boosted Strength: 30%Duration: 5 turns duration increased to 5 turns. Also remove 1 debuff from all allies. provides a lot of support via Eternal Wisdom30% boost to ATKMultiplier: Normal, 35% boost to double attack rate, and 10% boost to triple attack rate for allies with Wind ATK UpWind ATK is boosted . At level 95: 10% Bonus Wind DMG effect for allies with ShieldNext ATK received will be ineffective for a fixed amount .. At level 90, it even provides this on a permanent uptime, though the added debuff removal might at times be worth be worth saving up (especially if there are other ways to provide the buff)
Power Seeker200%-900% Wind damage to a foe based on how low Scathacha's HP is (Damage cap: ~720,000). When Dragon's FuryNext Power Seeker's DMG and DMG cap is boosted (Can't be removed) is consumed: Damage increased to 300%-1400% and damage cap increased to ~1,440,000. At level 100: Also gain JammedATK is greatly boosted based on how low HP is Strength: 26.6%-80%Duration: 3 turns and Guaranteed TAGuaranteed triple attack regardless of Triple Attack Lowered debuffs Duration: 1 turn . is her personal damage button, though both the direct skill damage and the JammedATK is greatly boosted based on how low HP is at level 100 rely on lowering her HP, be it from her third skill or other factors. Since her Charge attack at 5★ resets it's cooldown, it can (and should be) used fairly often at that point, though before that point it would be better to save it up for the general power boost granted by the charge attack.
Dragon's HeartAll allies gain ShieldNext ATK received will be ineffective for a fixed amount Strength: 25% of their max HP (Max: 5,000)Duration: Indefinite worth 25% of their max HP (Max: 5,000). (Consumes 25% of their max HP.) effectively converts a quarter of all party members HP into ShieldNext ATK received will be ineffective for a fixed amount , perfect for getting Enmity effects (including her own Claw of the DragonBig boost to all allies' ATKMultiplier: Unique based on how low Scathacha's HP is.) rolling without taking the full risk of lowered HP (though with the 5K cap, more developed grids won't gain nearly as much protection as they sacrificed). At level 95, Eternal Wisdom30% boost to ATKMultiplier: Normal, 35% boost to double attack rate, and 10% boost to triple attack rate for allies with Wind ATK UpWind ATK is boosted . At level 95: 10% Bonus Wind DMG effect for allies with ShieldNext ATK received will be ineffective for a fixed amount . also grants a Bonus damage effect to party members with shields active. While it should definitely be used right away at the start of a fight, later reuses might need to be considered carefully. Since it can't be used if any party member has less than the required amount of HP, characters with healing skills might be useful for counterbalancing it, or it might even be preferable to just have other sources of Shields available.
Synergy
Characters
As Eternal Wisdom30% boost to ATKMultiplier: Normal, 35% boost to double attack rate, and 10% boost to triple attack rate for allies with Wind ATK UpWind ATK is boosted . At level 95: 10% Bonus Wind DMG effect for allies with ShieldNext ATK received will be ineffective for a fixed amount . works with other sources of buffs besides her own, characters such as Niyon or Grimnir are helpful to keep the party shielded (the later also works well with her essentially permanent party-wide Wind ATK UpWind ATK is boosted at level 90).
This aspect is somewhat less relevant for Wind ATK UpWind ATK is boosted at level 90 when she is able to keep it up all the time, but at lower levels or in battles that like to remove buffs from the party a secondary source of the buff, such as Jeanne d'Arc (Summer) or Morrigna might also be useful.
Scathacha can hit the skill damage cap with a standard Tiamat Bolt grid at low HP, which makes the Skill DMG Cap perk effective.
TA, Critical, and Wind ATK are standard attacker perks, which you can get in no particular order.
Options
HP and Def perks make her a bit more hardy to compensate for her wanting to stay at lower HP percentages. HP perks can also help her reach the cap for the Shield buff, though they also lose some value when she already has enough HP from other sources.
If going for a defensive style, you can reduce Critical or Enmity stars for more defensive perks if you are already reaching her damage caps.
Extended Mastery skill is also a defensive option, though it is unreliable.