But it's fun!

Okay, then let's do it!

As for redemption...it's from a human perspective, but can be applied to nonhumans.

Yes. From a human perspective. But not from an unbiased perspective. Now obviously we could argue about whether as humans ourselves it is actually possible to look at it from a truly unbiased perspective but I think it is.

You could "redeem" a wild dog, for example.

I disagree. You can train a wild dog. But redemption requires the ability to think, to differentiate between "right" and "wrong". Redemption requires the ability to understand and reflect on your actions. When you train a dog you don't teach him "right" and "wrong" with words but with actions. He understands that he's not supposed to do one thing or the other because the pack leader is going to "punish" him for it and at some point the teached behavior becomes ingrained in him. But that isn't the case for all dogs that is why domesticated animals are bred by humans. In animals biology is the most important factor for how the animal behaves.

For us humans biology is also an extremely important factor but unlike animals we're sentient. We have to ability to consciously override our biological programming. But even among humans there are significant differences concerning that.

So I think for human concepts like redemption or morality you need to have awareness or sentience. From the perspective of a human a trained wild dog has been redeemed but from the perspective of the dog he's just acting the way he was taught by his pack leader. Or the way he was bred for. Or both.

That's almost the definition of amoral. They are without morality.

Yes but that's from the viewpoint of morality. Morality is a strictly human concept. From the viewpoint of humans demons are amoral. From the viewpoint of nature demons are neither moral nor amoral because the concept doesn't exist for them.

Not sure if that is a good comparison but I'd compare it with blindness. As people with sight we would define seeing "nothing" as seeing complete darkness but that's not what blind people see. Blind people truly see nothing. Darkness is something. Darkness is the absence of light that you can only perceive if you have a functioning sense of sight. Nothing is what you see at the back of your head. Some guy somewhere wrote about his father who had a blind spot in one his eyes where he truly saw nothing. Which meant that if something was in that blind spot it simply disappeared. There was no spot of darkness or anything. Just nothing. So amoral is the absence of morality but requires the concept of morality. Just like complete darkness requires the sense of sight.

So you are correct from the perspective of a human. But if we look at it from an unbiased perspective saying that the demons in Frieren are amoral and irredeemable is like saying a hurricane is amoral and irredeemable. The concepts simply don't apply to them because the necessary foundation doesn't exist.

I'm always trying to look at these things from an unbiased perspective. How successful I am at that I can't say. At least not unbiasedly.