More or less. Paarthurnax has been my mentor and Odahviing well... He took some time to warm up to me. He's a formidable ally and I can call on him but I don't know if he'd be able to reach me here.
Durnehviir is bound to the Soul Cairn. He went to the Soul Cairn to gain more power and knowledge and the Masters there tricked him into guarding over an immortal. Now that he's been in the Cairn for so long, his body is attuned to that realm and he can't stray for long before he's pulled back down. He said he would serve me in exchange for my calling him to the surface. He misses being above ground in the fresh air, and seeing the sunlight.