[Chazar]

I thought that throughout a battle, the ids are traversed either increasing or decreasing (but the order is kept throughout a specific battle).

At least I think there is a recommendation to have all Communion Masters shown close together in the middle and Communion Slaves in front and after the masters, so that at least half the slaves can still act for themselves (Communion Slaves only act if no Communion Master has acted yet in that Battle round).

If the order would always be increasing, then one would prefer Communion Masters always to be at the end or start (depending on whether it is desired to have the Communion Slaves acting on their own).