From Gineipaedia, the Legend of Galactic Heroes wiki
Extra-Terrestrial, or alien life, is a term used to describe any living organism that evolved on a planet other than Earth. In the Legend of Galactic Heroes setting, naturally habitable Goldilocks planets exist naturally, which would indicate that extra-terrestrial plants and fauna do exist, which may also indicate the existence of various other living organisms. It is also possible that even these planets are barren, and that all living organisms on the surface of these colony worlds were brought over from Earth as part of a terra-forming operation.
- The absence of alien life, of any kind, and the establishment of a single massive pan-galactic empire in LoGH is very similar to the Foundation setting favored by Science-Fiction icon, Isaac Asimov.