Azura! But...

seeing as urs is atk- u really dont want to maker her offensive, (most dancers dont want to battle anyways) so building her defensively is prob the best way, u can stack as much spd on her to help her avoid doubles, or give tannenboon+ like i did to get extra bulk+spd+atk when they try to kill my azura. or u can give her berkut lance and make her tanky on the res side while giving her glacies or iceberg to deal some damage. fury is always a safe bet. any chill or WoM is a good Bslot for dancers. maybe drop a miracle on her so she may survive a hit if she ever gets miracle to proc

I prefer -Atk on Dancers/Singers so that I can focus more on their defense more, my 4*+10 -atk +spd Olivia with Ruby Sword+ worked splendid even killing Hector's with ease

If she's a dancer, you don't really want her attacking since she's gonna be support anyway. WoM in her B slot is fun for a teleporting singer. If she's already -atk, you could just completely throw away that stat and stack Fortress Res on her A slot and Seal, then give her Glacies so she can do more dmg by proccing that since her 28 Res isn't too bad. Miracle probably isn't too good for her bc of the high cooldown, maybe Pavise or Aegis if you want extra defense.

If you have the resources, you could turn her into a red counter by giving her Swordbreaker, TA3 and Harmonic Lance. Hopefully the bonus dmg from type advantage and extra damage from Harmonic Lance, along with doubling from Swordbreaker should let her secure red kills.