Katie and Alicia have always been a pair. Everyone who knows them runs their names together, as if it was unthinkable that they should ever be separated.

For a while, they brought Angelina into their little group, since she was their third Chaser, and Oliver always called them "Katiealiciaandangelina", or just "Chasers". In terms of Quidditch, it's still that way. They're not sure Harry even thinks of them as separate entities, and the twins seem to think that's the natural way to be. They're used to being "Fredandgeorge", after all.

Since the Yule Ball, they don't see as much of Angelina off the Quidditch pitch. She's part of "Fred and Angelina" now, and in some ways, their trio's back down to two. They don't mind. After all, they were enough for each other before they met Angelina.

And as only she knows, they're a pair in more ways than one.