Four human brothers, too similar in appearance to be anything but quadruplets, but they are not. Their family singing/tumbling act didn't work out so they now do all the male parts in the opera's productions. Despite their similarity, the brothers consist of two tenors, a baritone, and a bass. It's hard to keep track of who sings which.

What people know about Hatter, Batter, Cinder, and Tam:

• They're brothers


• It's nearly impossible to tell them apart; despite that, they're not quartuplets (or any combination of twins)


• Also despite being identical, between them they sing bass, baritone, and (two of them) tenor


• They are loud and rambunctious; originally they had a family tumbling and singing act, and they still like to jump around and make a lot of noise


• They get bored easily, for instance when doing chores


• Their family act failed because collectively they have the financial sense of a flock of sparrows. That's why they joined the opera company, and they seem to like it

 

And that's it. Even the other members of the Swallowtail Opera Company don't know much else about the brothers. They like to party, but they keep things pretty shallow with everyone but each other.