User blog comment:Xilinoc/Ch. 599 - Too Early To Win, Too Late To Know/@comment-4822693-20141004225027/@comment-11051098-20141006141504

Interesting theory. But this would mean that also C, M and X which were introduced last week, are elite Sternritters, which means the lower division C, M, N and X are still unknown, making the elite Sternritter list at this point Also, if we read Askin's words literally, he's one of the lower division Sternritters, but was included in the elite force. This could mean that his signature ability is special in some way. Or, his words just mean that he was the only Sternritter who was summoned from the Seireitei below, while the 3 others were already with Yhwach, inside his shadow.
 * A, Yhwach
 * B, Jugo
 * C, Pernida
 * M, Gerard
 * X, Lille

The one thing that IMO speaks against this theory, is that so far Kubo have introduced Sternritters for different letters only. If C, M and X + Yhwach and Jugo are part of an elite division of 26 "new" Sternritters, then he could have chosen any letter for Pernida, Gerard and Lille. But so far, he's only done different letters.

This doesn't mean much, but to me it seems like there is only 1 set of 26 Sternritters, since Kubo's always introduced different letters. But I do think the theory of 2 x 26 makes sense, seeing as there's so many Shikai/Bankai still not revealed and so many characters that still hasn't been involved in the war, and only a handful of Ritters left to fight them.