Lumineth: Enduring as Rock

[T10]

Looking at the rules for adopting the Mountain Stance. This is clearly optional. Does adopting the stance cost you anything, e.g. is it not usable along with any other ability? Is there any benefit to not adopting the Mountain Stance?

The Alarith Stone mage both gets the Enduring as Rock and has the Stonemage Stance abilities. Is there any rule that says "stances" are mutually exclusive? 

[Aelfric]

The stance has no downsides.  Also the two stances can be applied at the same time.  There was likely an earlier beta version where there were several stances and you had to pick one each turn.  This morphed into what we have now, but they didn't (forgot?) remove the need to state that Alarith units were in the stance.  

Basically, just say at the start of the game that they are always in Mountain stance - your opponent should be ok about it.

[OkayestDM]

Several people theorize that more stances may become available as other aelementari temples are revealed, at which point we may find ourselves choosing between different stances to receive different benefits.

Whether or not that will be the case only time will tell, but presently there is no reason not to use Enduring as Rock, and the only potential downside to the stackable Stonemage stance is the limit on piling in.