I think it could definitely work with an oath of vengeance! Probably not oath of the ancients or oath of devotion, though. At least as the “character creation” screen starting class
Yes, you're probably right.
But there's aways divine intervention if you're really set on playing whatever. Durge was in the pod unconscious for a bit, any god could have visited them then.
I use that excuse as to why my Durge is a Seldarine drow since drow must choose who they worship at character creation by way of their subrace. And you could always take one level into Cleric for the character tags after they "find religion". One level in the War domain worked well for my Ranger.
