Eternal Sonata

Nearly all characters can dish out insane amounts of damage endgame apart from Beat and Polka. Fredric has the most powerful special attack(doing close to 500k damage with 32 echoes) but his shadowattack isnt nowhere nearly as good(but you get a decent cloak that takes care of that). If you finish an optional dungeon called mysterious unision, Retto, Jazz and Falsetto* will get really awesome weapons so might consider that as well. If you enjoy playing the twins they are really ok too though. For absolute max damage possible you would want to go with Jazz, Retto and Fredric for your first playthrough. You might want to use someone else apart from fredric though for reasons you will understand at the end of the game and until he gets his ultimate special attack he isn't really any good, so I would for an easy game suggest retto, jazz and falsetto or viola(if you dont have money for items to heal).

I used Allegretto and Falsetto for their strong attacks and they are much faster than Jazz. I also used used Polka mainly for healing but Nether Wave is very strong as she levels up. Viola is good when attacking from afar. The twins are good for getting echoes up. Beat is pretty useless and Frederic has some strong special attacks although his healing abilities aren't as good as Polka's. If your playing the PS3 version Serenade is good for special attacks and Crescendo is good physically but only learn two abilities. Use a team that works for you.

It depends on your battle style really. I used Allegretto, Jazz and Viola. Allegretto mostly because I've used him from the beginning that his attacks hit pretty well and make up for how slow Jazz can be. Jazz is slow but strong, his normal attacks as well as special dealing some good damage when you've got better weapons. Viola is my healer, since she can heal both in the light and the dark. I'm the type of person to hold onto my items so I don't like using items to heal and relie a lot on healers ^^
But you could be different. Just hope this helped a little.

Beat is pretty useless unless your taking pictures, Polka is the best healer overall in the later portion of the game. Viola is the cheapest character i believe since her single shots from a distance can rack up to 10k early game without much effort and do so much as 90k per hit later on making her a very useful member, plus she gets light and dark heals so she can act as medic. Falsetto/Salsa/March do very well as your combo builders and can dish out a fair amount of damage, while the twins help because of their unique skill power-ups. Jazz is great tanking and is a great defender, Crescendo is even better defender if your playing the ps3 version but his skills do limit how useful he is in battle due to only having 4 (2 light and 2 dark). Fredrick is a pretty solid single target medic and is pretty good all around throughout the game. Serenade is pretty good when you can get her to 24 or 32 echo, her shot skills can really do some damage but her heal is pretty much useless by the time you get to use her and Polka far outdoes Serenade once Polka gets her cheap heal-all. You don't really get best characters to use like that until the end of the game but Falsetto, Polka and Jazz/Allegretto make a pretty beastly team, as do Fredrick and the twins if you like building your echoes quickly and doubling the damage and reducing it too. Depends on your preference really but these two teams are pretty powerful, experiment and see what works for you.

Hmmm...I love Beat. My party is Beat, Frederic, and Polka. It you have Beat far away, but close enough to where his gun special attacks will connect, he can do really good damage. Frederic and Polka can both heal everyone. I have Polka to heal, Frederic as the front line attacker, and Beat as the distance attacker.

Viola is really good though, besides her healing. Once Polka and Frederic get Blossom Shower and Tri-Clementia, respectively, you really don't need Viola. But if you use Viola to attack using regular attack and she is close enough to connect, she can do massive damage. Her regular attacks for me take off around 30,000 per attack and it also builds up echos.

I find that Frederic doesn't get as many equipment as the other characters, especially Retto, which really sucks.