I had often thought of them as my family, but to hear it from their own mouths, to hear that they felt the same way- it gave me a whole new idea of vengeance.
Either "Since Elder Soyala" or "Since Soyala, an Elder," not the way you have it. Little stuff, but still, a bit jarring.
I'm not clear as to whether this is the first chapter of the book or not. If it is, this is a lovely opening line, and draws interest perfectly into what's happening. I would advise you to spend a little more time here in the first paragraph giving more description to the main character. How Callum looked when found by the elders, the state of dress, hair, eyes, lingering scents not blown away by the scrape of the desert winds, peppering in details as you go. Just my personal preference when first meeting someone.
The names of the various 'partitions' are interesting to me. They suggest without being overbearing that there was some kind of purpose in naming the various portions of this country/continent/world we're working in. Has a very "Dauntless / Abnegation / Candor" type feel to it. Also not giving us the names of every single one of the others right up front is nice, holds interest for further revelation.
Opportunity for a tiny bit more cultural revelation here. For example, "I drew the rune for Continuance, for Key, for Home. For my own name, the angles sticking out sharply the way I tended to by my appearance. It looked strange beside the other, comfortable runes, like watching my own life matched with the rest of the lives around me on the sands." Deepens things through internal identification.