You probably have heard various Nick Fury fan theories before; Odin is hiding out as Nick Fury, Nick Fury's secret identity is Samuel Jackson, or that Nick Fury is a Skrull.
Samuel Jackson is reported to be having a major role in the new Captain Mavel movie. Talk is that he may even get top billing or equal billing as Brie Larson. Why? The movie will feature the Kree-Skrull War as part of the origin story. Nicole Perlman, co-writer of the new movie, has indicated a new origin story will be used. Other rumors point to Mar-vell being in the movie. This movie is supposed to be very important as a prequel to the Avengers, possibly a reason Nick Fury created “The Avengers Initiative”. Mar-vell was the campanion/mentor to Captain Marvel. With all this in mind, could Nick Fury be Mar-vell? Could he be the one that taught Shield how to use the alien technology? Nick Fury is the connective force in the MCU that links all the characters together. If he is Mar-vell, this would be the last link.
Is there any evidence?
In “Marvels Agents of Shield” Raina has clairvoyant abilities after undergoing the Kree Terrigenesis. If Fury/Marv-ell is also a clairvoyant, in the “Age of Ultron”, it would explain why he knew to build a safe house for Barton and then to show up without every being notified at the safe house, the location of the Scepter, create and enact Theta Protocol, and to conveniently have Helicarrier No. 64 show up for evacuation in Sokovia. Was it not convenient that when he was injured in “Winter Soldier” there was a private medical facility for him? Could it be that he can't go to a regular hospital because it would expose him as a Kree? There are many other plot holes that the Fury/Mar-vell theory could fix.