We know there are (were) at least 13, and with Lahabrea, Igeyorm and Nabriales gone, we may see the other 9 with their own individual plots. They seems a really big Chekov's Gun to just leave hanging while only Elidibus does his thing.
However, those 13 we know of are maybe mayor Ascians, do we know how it works with lesser Ascians (Trevanchet? the ones fron the SMN quests?)? Are they just servants of the 13 or do they have their own plots and machinations?

*Casts Summon Moose-senpai*