I have yet to meet another dog with the same spelling as my boy, Orien.

I usually call him Rien, pronounced Ryan, or just Ri (Ry).

I've met a few Orions, all of them huskies. I guess it's a nordic dog name.

His name came from a Cynthia Voigt book called On Fortune's Wheel. The character Orien is the name of the Lord that comes to the protagonist's rescue and is generally her knight in shining armor and true love. That topped with the fact that his bellflower blue eyes are commonly mentioned made me really want to name my puppy that (blue eyes are a disqual in Mals, I have the weirdest sense of humor).

And of course, my knight in shining armor, no matter how I pronounce it, fits his namesake well.