Harriticus wrote:The Astartes probably would get along the worst with Ecclesiarchy priests that accompany IG Regiments.
It probably depends on how obnoxious the individual Confessor is, and how much the Chapter dislikes the Ecclesiarchy on general principle. The clergy being Warrior Priests essentially makes them "brothers in arms" just like the Guardsmen. I suppose it comes down to the level and the exact direction of one's fanatism, as well as to which Ecclesiarchal faction the Confessor belongs to. The clergy is a bit split on the issue of how to best deal with Space Marines, them on the one hand being the Emperor's sons, and on the other being what some would call mutant heretics.
I'd suspect that in general there would indeed be a lot of mutual distrust, but in some cases I could see them get along - especially where a Chapter has served the Ecclesiarchy before, such as the Black Templars protecting/recovering a holy relic on Armageddon. There is a certain overlap between the Ecclesiarchy and the Astartes, and although it is mostly lip service to keep matters in order, there are precedents for cooperation or (in the case of the Sisters) even mutual respect.
Something that is often forgotten in this aspect is that Guardsmen, and even moreso the Commissars, are
all adherents of the Imperial faith. Commissars in particular were essentially
raised by the clergy. So if a Space Marine really has a big issue with religion, it's likely he would not get along with any of them.
ALEXisAWESOME wrote:I doubt that they would be overly friendly (but Cain seems to make a ''friend'' of a tech marine while aboard)
Ya, Cain is the one big exception that seems to defy a lot of fluff about Commissars from
GW's books, including what it takes to become one...
Still agree with your overall assessment, tho!