What would be the most apt word in kanji, for "Animal world"?

Question

Okay, that may sound a little confusing, and no, not looking for the name of a zoo or theme park here XD

Essentially, simply put, I'm writing a novel, and for that, building a world around it. Yes, there is no need for the Kanji - I am well aware of that, and yet, I feel like using kanji for specific phrases.

My story has several locations. Much like a heaven - earth - hell, except they are based on a reincarnation and enlightenment system instead of an afterlife based on a moral judgement sort of thing. Those souls that achieve enlightenment and 'ascend' beyond their eternal cycle of death and rebirth in Jinkai by discarding their current worldly attachments, go to Tenkai, where celestials and other deities live. And "hell" is fully inhabited by demons, not inherently evil, merely fundamentally different to those that live on "earth". Yes, sinners and saints don't matter in this universe. Morality is a human construct (at least in this story if you would disagree on that, as I really don't want to be dragged into a meaningless debate).

Anyways, the three worlds are as such:

Tenkai - Celestial World (天界)

Ningenkai/Jinkai - Human World (人界/人間界)

Makai - Demon World (魔界)

Particularly, using Yōkai instead of another phrase for Demon, such as Akuma, as that would be more 'Devil' I believe, and would have more 'Evil' connotations. I thought of using Mazoku, except that implies 'Demon Race', as in a singular species. I want 'Demons' in Makai to be the equivalent of all 'Organisms' on "Earth", as opposed to merely being the opposite of Humans. (But, I would very much appreciate if someone could provide a general term as such to use the would imply Demons - or even something like "Others" as in fundamentally different from Earth's inhabitants, as Yōkai's meaning is closer to ghosts and strange apparitions.)

As such, here I come to the crux of the matter. Particularly, the naming of the Human World. I believe that sounds rather pretentious, as Humans alone are not the inhabitants of Earth. Yes, they are the apex predators and all that, but to keep Makai and Jinkai parallel while giving the impression that Makai is not of only one species, but composed of several diverse set of beings that are merely fundamentally different to all creatures on earth. As 魔 (Demon) is up to interpretation, it does not have the same problem. For example, there would be demonic equivalents of dogs and bacteria as well, on Makai.

So, is there another prefix I could use, instead of Jin or Ningen, that would imply all the known organisms on earth (animals inclusive of humans at least, preferably others outside the animalia kingdom as well, such as microorganisms)? I would also like it if it is simpler in terms of the number of syllables, even if the term itself is particularly obscure.

I understand this is a very tall order, on top of a very lengthy request. I think the above would be important context as to understand the exact implications of my query. If not, I apologize for the long read, so thanks for at least putting up with me XD Thanks in advance for the assistance as well, if I may be so forward as to presume as such? :D

Answer 1

人間界 is very commonly used for this purpose, and I recommend you accept this term unless you really have a good reason. 人間界 just means "the world where humans exist", and everyone understands that there are also other animals, plants and bacteria and so on in 人間界. Another good option is 地上界 (Chijōkai, lit. "the world on the Earth") if your other two worlds are not on our planet. 自然界 (Shizenkai, lit. "the world of nature") may be another option, but in many works of fiction 自然界 can be an opposing concept of 人間界 (for example in movies like Lion King or Princess Mononoke), so you'll have to explain your definition of 自然界. 動物界 would be the literal translation of "Animal World", but it obviously doesn't meet your requirement.

I think 魔界 is OK as long as this is the term named by humans, and humans are more or less afraid of the beings living there. Residents in 魔界 (ie 魔物/魔族) are not necessarily evil in many works, and in some cases humans and 魔物 live happily together even though they're still called 魔物 from 魔界. (Think of Monsters Inc., though I don't know whether their world is actually called 魔界 in the movie)

But if you want to avoid the "evil" and "dark" connotation of 魔界, I also recall seeing 冥界 (Meikai) and 幽界 (Yūkai) several times, both of which don't have a fixed definition and just feel like "yet another different world which is not bound to flesh" to me. Please try Google Image Search before accepting any of these. Another option might be 異界 (Ikai, lit "different world") if you really want to emphasize the "parallel" nuance. This essentially just means parallel world in general, but I think you can determine to use it as a proper noun in your novel.

Answer 2

This is definitely a difficult question to answer. It might be smart to do some research into religious terms (i.e. Buddhism) where they take in to consideration that there are other worlds than our own. Otherwise you could go more biological in your approach. For example organism world: 生物界(living creature world) or 生体界(living body world).