In all our exploration of the galaxies, humanity has never come across another self-aware starfaring race that breathes our atmosphere and eats the same kind of food we do. There is sapient life out there, but it is as remote and impossible to understand as the AIs, if not more so. Thus, we do not encounter alien characters in Torei (although humans themselves have changed a lot through natural and artificial selection as well as body modification!).

This is not to say that there is no alien life. Humanity found signs of organelle structures in gas giants, social behaviours in xenobiological yeast organisms, methane-breathing monotreme-like creatures, and self-organizing patterns in the "great conveyors" of planetary magnetospheres. But we never found cat-people, snake-people, elf-people, or warlike people with ridged foreheads. We never met 2-metre-high races of tentacled cowards, mutants living in robot shells, or almond-eyed naturalist imps in flying saucers.

If non-human spacefaring intelligence exists, then it is impossibly vast and inscrutable and does not care about our realm. Perhaps it has no need for things like water and oxygen that we depend on, or perhaps it does not interact with the electromagnetic spectrum, or perhaps it's just been sleeping for the past four billion years and is about to wake and devour us all.

That which does not kill us, makes us…stranger. Edit

This is not to say that spacefaring life is all boring old original human forms. Life spent for thousands of years in different environments will have selective pressure. The connectedness of all stars makes speciation unlikely, thanks to interbreeding, but Torei's isolation makes it an interesting time capsule for the human genome.

In addition to this, Torean biotech has modified the Torean humans to survive on their half-made world. Tourists come to Torei to seek the more advanced work from the Ministry of Improvements, and many no doubt have exotic forms they wish to inhabit.

If there are exotic creatures capable of engaging in your story, they will most likely be modified humans.