The term 'Cosmos Creator' refers to the late astronomer and astrophysicist Carl Sagan, whose five-letter surname is given in the crossword solution as SAGAN. Sagan was an American scientist who was renowned for his work in astronomy and astrophysics, as well as his popular science writing. He was a professor at Cornell University and was the author of the book and television series Cosmos, which explored the universe and humanity's place within it. Sagan was also a strong advocate for the scientific method and the search for extraterrestrial life.