Rayne — the stars, history, light, truth, and very, very much more.
Katsuki — fire, heat, warmth, blood, success, victory.
Deities don't have defined domains. We're vaguely assigned something and get to control it. Mortals will find a concept of something and say, "That reminds me of ____" so many times that that deity is in charge of it now. That doesn't mean we like it, but so be it.
My wings (left), Katsuki's wings (right).
All gods have (at least) two wings, two arms, two legs, and two reproductive systems, so to speak. We experience gender, a little differently than humans, but it is still experienced, just unburdened by the concept of being assigned to one at birth. It really amazes me how some mortals could see others as disgusting creatures just for bypassing their sex to feel more comfortable, but I guess you're flawed for a reason.
There are other gods. Many of them, actually. I'm referring to the ones that control Alauriaus, though. We don't "marry," but we love, and it is the most horrific, vulnerable, selfless thing to happen. And we do it again and again, through hardship, just as a human would. Why? I'm not entirely sure. The want — need — for connection is deeply rooted in sentience, no matter how you want to put it.
Deity love transcends many, many dimensions, though; dreaming of your lover, letting your conscious soul move to a different place to be with them, you know, the usual. It is why when you humans developed technology past the sky (have you done that yet?), into the blackness that suspends stars and into the stars themselves, they burned. This is me and my lover's essence intertwined.
A part of you and your loved ones will be intertwined someday, somewhere far away from the dirt beneath your feet and blood in your veins. Just as every soul before and behind you has. Only a little bit of your essence, though. The rest goes somewhere else.
Remember: when you look at the stars, remember that fate will redirect you to love's arms again. Amor vincit omnia.