Quasar is Wendell Vaughn - a failed S.H.I.E.L.D agent who was deemed unfit for field duty and instead given a job in the organisation's research division. On an early research assignment, he was part of a team studying the Quantum Bands, which had been taken from the deceased anti-hero the Crusader. When a test pilot who was selected to wear the bands initially proved very successful in their usage, but died when he lost control, Vaughn put the bands on as the criminal scientists A.I.M. (who are already in the Marvel Cinematic Universe) launched a full-scale assault on the facility in a desperate attempt to repel them. When the energy build-up of the bands began to overwhelm him as it did with the test pilot, Vaughn decided to simply relax and go with the flow. To Vaughn's relief, the build-up abruptly dissipated and he realised that the key to wielding the bands was to possess a flexible will, rather than an indomitable, uncompromising one. Basically, his lack of a killer instinct made him a suitable wielder. Vaugh became a hero and, after first going with the names Marvel Boy and Marvel Man, he settled on calling himself Quasar. As Quasar, he possesses the abilities of energy manipulation, teleportation, the creation of solid light constructs and flight. As a S.H.I.E.L.D staff member, he would be very easy to introduce in to the Marvel Cinematic Universe - in fact he could be brought in on the Agents of S.H.I.E.L.D. television show and given Avenger status when Thanos puts the universe under threat. Quasar was present in the climatic conflict with the Mad Titan in the comic book arc, so it certainly makes sense that he would be involved in the movie depiction.
