There are several versions of this character that have been intrinsically linked with the Guardians Of The Galaxy and Thanos over the years. Wearing the ultra-powerful Quantum Bands that designate him or her the protector of the Universe, Quasar is less a name, more a title that is passed down to whoever the bands have chosen at that time, a little like DCs Green Lantern (you can see a pattern developing here). Phyla-Vell was the second Quasar, and actually a member of the Guardians for a long while, but shes less recognisable and less useful to the Marvel Cinematic Universe than her predecessor Wendell Vaughn, who were focusing on here. Vaughn was a S.H.I.E.L.D. agent who came into contact with the extraterrestrial Quantum Bands while working security at a research facility dedicated to studying them. While S.H.I.E.L.D. doesnt exist in any real form in the MCU at the moment, that doesnt mean that the research facility doesnt. Its perfectly possible that Guardians Of The Galaxy antagonist Ronan and his cRonies (we bet thats what he calls them in his head) might go looking for this fantastic source of power and trigger Vaughns transformation. Possible but not plausible. Still, Quasars another of Marvels cosmic heroes who could easily do with his own movie.