When elders accepted new elder in the council he became elder 13th.
What we can assume from that?
Now look the 4th elder is Kravei. He betrayed Rai 900 years ago or so which resulted in Rai go hybernation by unknown conditions.
The organization exists for more than 500 years.
Logically, 1-3rd elders are for sure some ancient powerful nobles. And probably other elders to number 10 are quite special too.
Thats why they said something like elders 12 and 13 are just formal, they are not the real elders, as they dont live to that status.
Edited by Evgeny, 08 June 2012 - 02:20 PM.