I started my first Char a few days ago and found the immaculate Cave.
Inside is a hostile immaculate, i can't say for sure, if this is the friendly Immaculate that is hostile for some reason or is this is just a random hostile Immaculte. I didn't join a faction yet.

Regarding to the Wiki and the outwatd forum the immaculte should be friendly, expect for members of the holy order.

Anyone some experience with the immaculte's Cave?

He is friendly for me, I can talk with him and he gives me either an item or a power.