Shared A Thing I'm Writing With My Friends And It Sparked Some What If Thoughts Of "What If There Was

Shared a thing I'm writing with my friends and it sparked some what if thoughts of "What if there was some being that actively hunted the Links? And was very capable of killing them?" and I suggested the Fierce Deity. This resulted in me having to explain what that is and realizing that there's not actually much lore for it, excluding the manga, so now for me the idea has spiraled into this.

Basically, now what if even after the war with the gods, demons still remained in hiding, waiting for their King to return from his seal. But now that Demise has been killed, they've become susceptible to normal weapons and not just to holy power and the Master Sword. Even then, their rage drives them out of hiding to kill the ones responsible, which in their eyes, is literally any living thing they come across.

Enter Oni, the self proclaimed Demon Prince; no other demon's been strong enough to dispute this. He emerges from the volcano and has been on a destructive path towards the Hylia Statue, where Demise had been sealed and where a small settlement has been trying to grow. Link and Zelda hear rumors of Oni approaching and go to confront him, the only ones strong enough to fight him.

A brief excerpt of what it might be like, plus a vagueish description of Oni:

'There had been rumors of a pale white monster covered in strange patterns with long hair like a mane, along with massive horns and fangs. But standing there, with its back turned to them, the Demon was much more humanoid than Link was expecting. A familiar shape. Its voice was grating as it turned to face them, "You are the ones who slayed our King? Left us vulnerable to your pathetic mortal weapons?" its blood red eyes narrowed, in stark contrast to the rest of its body.'

(not said there but the horns are the colors of fierce deity's sword because oni rips them out of his head to create it. then when he's done shoves them back in :])

Somehow they defeat him(after he monologues of course), but after the burst of light fades where Oni died, was an unconscious kid. Basically a smaller, like 10 years old small, and more human looking version of Oni. Pale skin and pure white hair, the strange designs on him are still there but not as many as before, and metal-like nubs where the horns were. He's basically naked because Oni was wearing those like big weird samurai pants I don't know how to describe uh if you know Terra from Kingdom Hearts yeah those.

Anyways, Link and Zelda are VERY confused at a child resembling the demon they just killed appearing out of supposedly nowhere. But they're nice enough to go over and pick him up off the hard ground, wrapping him in the sailcloth Link carries with him all the time. The motion wakes the kid up though, and at the sight of the two he immediately imprints on them like a baby bird. Yeah they're now accidentally parents to this demon child yay. Luckily the kid has no memory of being a demon, only knowing his name is Oni.

There's more I could talk about but that would end up as me rambling just some random ideas.