Valenthians were introduced to Xilas the Cold when the three Presences appeared.  They claimed Xilas was their master and their actions were in his service.  After the capture of one of the Presences, Xilas traveled to Valenth and met with Dr. Dreamscar.  He talked briefly to some gathered mortals while waiting for an official representative.  He explained he is a Prince; a Shadowlord.  He also said that leupaks had been seen traveling in his realm, apparently gathering some sort of scientific data. 

"Should one of you draw close to me, you would understand the title.

Shadows are devoid of light and heat, and so too am I. Some might consider me a daemon, but they hail from a more fiery plane than I. We are...the other end of the spectrum, I imagine.
There are many Princes of Shadow. I am but one." -

Xilas has not been seen further since this event, leaving us with more questions than answers.