Zest, the "goddess of destruction" created Haruka's body, and as far as I can tell, the body was made because (huge grains of salt here please)Haruka's original body got lost, and a new body was made for him... but the goddess did a little too good of a job and if she kept going would have lost her own, so she kind of just threw Haruka into it before she was finished and hoped everything would sort itself out? There's no special purpose behind Haruka getting her body.
Uh, I'll just copy/paste the browser translation of the relevant segment. Just to let you know, it will make enough sense that you can get a rough idea, but a proper translation will be so different that you'll be shocked at how nothing except the terms of a few concepts will be recognizable between the two translations.
For example, if the browser translates "Two elephants had tea." You will see a proper translation say, "It was like watching an elephant with how gracefully the trunk moved the saucer." It's that different. Without further ado:
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"That's right. Use your body and the shape of the magic element as a reference to make it, and your heart inside? I kind of put something like that in and adjusted it, but... I was like, if I try my best, my body will disappear, and I'm like, wow, what am I going to do."
He speaks in an unconventional way, but from what I've heard, it's clear that this person is indeed the god Zest, and that he 『created』 Haruka's current body.
Ultimately, this body is not Zest's own body.
"I've lost my body...?"
"That's right. My body was originally made to manifest with magic. I don't know if that's the reason, but that's how it is. Moreover, it seems to have been done too well, so even when I try to contact him while he's sleeping, he always ends up playing the ball. Well, I'm good at making everything. Being strong is important after all. Oracle is a bit noisy about balance and stuff... but oh well, it doesn't matter. I mean, that makes it hard to find. So he used a lot of magic tricks, and when the location became easier to understand and his body became a little more vulnerable, he would talk to me like this, but at first I couldn't get the words out of it, so I was really worried about what to do. You really get the idea of making it yourself and then having this. Well, that's what you mean by doing something for the first time... ah."
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Edit: Re-reading it, I'm thinking Haruka's male body got lost, and the goddess used her own body (substance) and the magic coming from Haruka... or Haruka's soul? (Shape) as a reference point. And then put Haruka's soul in the newly created body in a rush once the goddess realized her own power to manifest was running out, and just hoped the merger would complete on its own.
I guess?????? I mean, it really is a broken translation. If any of that is correct, then I guess that means the species was from the goddess, the gender was from Haruka's "magic" (soul?) and thus Haruka is growing into her body successfully?