Restating my question, In most of my history with Sci-fi games (Gears,40k,etc) and even on a lackluster sci fi wiki that Tyran is a human (Sci-Fi wiki entry: Tyran-A being who is of Human descent but is not truly human or a half human being/Half Human Descendent of the Human race) and now learning that Tyran is not really mainstream in science fiction, where did this term come from. Note: A entry from a dictionary style Wikipedia stating that Tyran in English and French is a word shorten from the Old Latin term Tyrant(dictators).
Perhaps this might be a possible answer.
The first installment of Asimov's Tyrann was the cover story in the fourth issue of Galaxy Science Fiction in 1951. The novel was issued in book form later that year as The Stars Like Dust.
The human-descended bad hats in this Asimov story came from the planet Tyrann. Perhaps someone adopted it as the basis of the term "Tyran"?