It was discovered Proto-Humans also existed on Carpathia. Stella Isen found a family of what seems to be, a Hominid life form upon Carpathia, one thousand years old. It is currently not known what form of life this is. (Episode 5)
Richard Tate was interogated by a vision or manifestation of himself created by the Host Force which mentioned the creatures, deeply implying that "they" had killed all of them before the humans arrived (Episode 7).