I see Boeruine's actions as primarily a power-grab, perhaps he was a Roele scion married off into the Boeruine family (if they only had a daughters, a junior Roele son would be welcomed into the family via marriage).

If he'd killed Michael (which would not have been publicly known about if he'd succeeded, then he would have retrieved his 'rightful place' as emperor without any major bloodshed - unless some dukes 'rebelled against him'. Of course when Michael lived a real war was inevitable unless Michael crept off into the sunset / pulled off an assassination / personal challenge.


On the influence of the church, I would expect that the priesthood was every bit as political as the rest of the nobility - and if one 'Roele' challenged another (for example when Boeruine challenged Michael) and the challenger was clearly stronger and more likely to support the church, then the majority of the priesthood would probably support the challenger and justify it later.

To avoid the problems of an absolutely dominant church (b/c it can prove faith) of priests utterly devoted to the creed (because o/w they lose spells etc clearly indicating which is in the right and which is the heretic) I put a similar restriction on priests as I did on mages in the campaigns I designed - so only a rare few priests can 'invoke miracles' - and they are not bestowed lightly, while the god is much more distant s less likely to give direction. (More accurately I removed them completely except as a guiding philosophy for the church, apart from anything else I feel uncomfortable role-playing a god as DM)

Given how strong some religions are in rail-roading thought in the real world, to keep a D&D game interesting you need something to undermine them, political intrigue within the priesthood is a good candidate - any organisation with that much wealth and power will attract a lot of parasites and ambitious types.

btw, I am not sure where your comment on summoning angels comes from - as far as I am aware there are no deva's / demons etc in BR, only Shadow World creatures (who can admittedly stand in for either) so the church shouldn't have otherwordly minions, not that it really needs them with spell casting priests, paladins, etc.