Halloween L'Arachel

Weapon: Plegian Torch(+Spd) / Gronnblade / Gronnfox(+Spd)

Assist: Positional Assist

Special: Luna / Moonbow

Passive A: Atk/Spd Boosting A Slot Skill

Passive B: S/R Far Trace / Lull Spd/Res / Desperation

Passive C: Panic Smoke / Fatal Smoke / Preference

Sacred Seal: Atk/Spd Solo / Swift Sparrow / Blade Session

• Halloween L'Arachel is a rather standard player phase unit with a good offensive statline. Much like her contemporaries, including but not limited to: Valentine’s Lilina, Valentine’s Mist, and Summer Selena(her exclusive weapon is essentially only a slightly improved inheritable), she lacks any notable features that allow her to stand out when compared to green tome cavalry that possess exclusive weapons, such as Gunnthra. Still, thanks to her statline, Halloween L'Arachel is able to perform reasonably well as a player phase unit given enough investment, although the task of merging her is fairly daunting due to her status as a limited unit.
• Your usual Atk/Spd boosting fare works wonders for Halloween L'Arachel’s player phase potency. Skills such as Atk/Spd Catch and Swift Sparrow give her a massive boost to her offenses during Player Phase with minimal drawbacks, and some can have their downsides taken advantage of, such as using Atk/Spd Push 4 to reach Desperation range.
• L'Arachel’s best choice of weapon is the Plegian Torch, as it inflicts a massive Attack and Resistance debuff that can be enhanced further by debuffing the foe, although it’s an extremely difficult weapon to obtain. Gronnblade is also potent, although she has to keep a close eye on Panic inflicting skills, lest L'Arachel be turned into a sitting duck. Gronnfox is a more consistent alternative, but with a significantly lower damage ceiling. 
• S/R Far Trace is Halloween L'Arachel’s best B slot option, as canto allows her to leverage her high movement, although Far Trace is much harder to take advantage of than it’s melee counterpart due to the lack of extra movement alongside canto. Lull Spd/Res and Desperation are serviceable alternatives, giving her buff negation and safety from counterattacks respectively, and are much easier to obtain(especially Desperation).
• Panic Smoke and Fatal Smoke allow L'Arachel to threaten foes within 2 spaces of her attack targets with crippling debuffs, but these can be substituted freely.
• Lastly, player phase boosting sacred seals such as Blade Session are great options for L'Arachel’s seal slot, giving her another big boost to her offense.