Argh that fight took me so many attempts, I had to keep Frederic somewhere far so he could always do "Sacred Signature" to heal the team, but then he would go in for the attack.
I sometimes ended up with Beat who would always have to stay far away from Tuba. Whoever else either Allegreto or Polka would just constantly attack. I didnt really like her healing move (cant remember if it (orange glow, I believe) was unlocked for me at that point) but it was a long fight when I finally made it far enough.
Yeah but this battle you will hear "Sacred Signature" alot from when I did it. I would try to time it when the meter was full so then that character who was healed would have a turn to go in for the kill.
And keep everyone in like a triangle formation so that he could only attack one character at a time, and always go to the back of him. I dont think I was at level 18 though.
I have to replay this since Im stuck after