I liked the piece a lot, it feels different from what I usually read.
Leading with a "monster-type" character is an interesting choice (certainly a bold one) : we'll have to see down the road where that leads us, but for now, it felt quite different.
I don't know if it was a deliberate choice or not, but I only picked up the SF part near the end of chapter 1. For a good part of the chapter, I went between "fantasy-style" and "unknown-style". I was happy about that, but I worry that regular readers would rather know right away which side they're on.
The writing of the first chapter was nice, but I found the words "High Lord" and "Darkclaw" too present. At first, I didn't see it, but the sheer number of those bothered me at some point, and every time I read one of these, I cringed.
The part about the "High Lord" weakening felt a tad too obvious for me : the character noticing something and explicitly dismissing it did raise a red flag for me. Maybe you could just skip the part about dismissing the observation. I think that often, readers register what we write and there is really no need to say much for them to understand. They might not know it at the time, but down the line, they'll remember.
The naming of "Darkclaw" did bother me at first, because it was obviously a new name taken from his new body. If he didn't know how his body was shaped, how did he call himself Darkclaw? In the end, I understood that the High Lord did name him, though Darkclaw didn't understand why at the time, so my interrogations are answered, but I wish I had been given the explanation earlier, it would have saved me much grumbling.
I found chapter 2 interesting, even if it was more conventional, and yes, I think you needed to cut off from Darkclaw a little, to show us people we're more supposed to attach ourselves with.
The relationship between the two is well portrayed, so I wasn't bothered to find they were in a relationship at the end of the chapter.
I cringed when I saw the mirror come in : I told myself "that's it, the obligatory mirror description comes in". I was kind of relieved when you didn't use it fully. I see here the writer wanting to describe his character, but stopping in the middle because the device used is so bad he can't go on writing it anymore.
If you really want to describe the species, have her describe Felivas early, and only throw in hints about her own features (a strand of hair here and there).
I would also be mindful of "dialog info-dump", because at times, I felt like things were being said only for the reader's benefit.