Arciela
Note: ST stand for Single Target and AoE is for Area of Effect
Note: C65 stand for crystal level 65
What she do
BRV ATK
Magic attack - Steals enemy's BRV
Change to 2-hit AoE BRV ATK+ (Descension) after using Descension & Sight Unseen
      Deals extra BRV damage to debuffed targets
Debuff MAX BRV & SPD Down (lowers MAX BRV, SPD)
Change to 2-hit ST BRV ATK+ (Ascension) after using Ascension & Expunge Magic
      Grants party BRV based on own INT BRV
Buff Fast Cast (returns party's BRV to INT BRV in 1 turn following HP attacks or being inflicted with Break)
HP ATK
Magic attack - Expends BRV to deal HP damage
Change to 5-hit ST BRV + HP ATK+ (Darkest Hour) after using Descension & Sight Unseen
      Deals extra BRV damage to debuffed targets, deals 20% HP damage to non-targets
Change to 3-hit ST BRV + HP ATK+ (Harmonic Displacement) after using Ascension & Expunge Magic
      Grants allies BRV based on HP damage dealt
Buff Fast Cast (returns party's BRV to INT BRV in 1 turn following HP attacks or being inflicted with Break)
Skill 1  (Ascension & Expunge Magic)
Magic attack - 5-hit AoE BRV + HP ATK
Deals proportionate HP damage to each target, tremendously restores party's HP based on HP damage dealt, Removes all buffs from targets
Cancel Descension buff
Buff Ascension (raises own MAX BRV; restores a certain amount of party's BRV; raises party's ATK, INT BRV) and Fast Cast (returns party's BRV to INT BRV in 1 turn following HP attacks or being inflicted with Break) to self
Skill 2  (Descension & Sight Unseen)
Magic attack - 5-hit AoE BRV + STHP ATK
Deals 50% HP damage to non-targets
Cancel Ascension buff
Buff Descension (raises own MAX BRV, ATK; raises party's ATK; lowers all enemies' SPD) to self
Debuff MAX BRV & SPD Down (lowers MAX BRV, SPD) and HP Attack Disable (prevents use of HP attacks)to all targets
EX+ (3/3) Skill  (Naakual's Vengeance)
Magic attack - Slightly restores party's HP + 8-hit AoE BRV + HP ATK
Deals proportionate HP damage to each target, grants party BRV beased on HP damage dealt
Buff Heirloom (raises own MAX BRV, ATK; restores a certain amount of party's BRV) to self
What can she provide
BRV and healing to the party. Her c65 raises party's ATK for 5 turns. His c10 allows her to deals slightly more BRV damage when using chain attacks. His C68 boosts party's INT BRV, MAX BRV. She has a C sphere: After inflicting Break or attacking target afflicted with Break: Grants party member BRV based on 10% of individual INT BRV at start of party member's turn for 3 turns
What can she be
BRV battery support, dispeller, healer, damage dealer
Overall thought
She can battery BRV, heal, dispel, her c65 raises ATK and she can chase (chain ATK). She can tag with anyone, as she is able to chase, tagging with a launcher would be ideal. Her skill 1 and EX+ are AoE with skill 2 having 50% damage to non-target. She is also able to debuff all targets. Stopping them from doing HP ATK.