Captain Marvel is all costumed - up in set photos for Avengers 4, but what some fans believe is a color error is actually totally in comic book canon. (cbr.com)
As has been exhaustively documented, writer - director James Gunn has confirmed it will not follow comic book canon and be Prince / King Jason or J - son of oh - who - the - hell - cares (editor's note: Spartax, because I couldn't let that go). (newsarama.com)
(That said, considering The Grandmaster is one of the universe's immortal Elders who, in comic book canon, can cause death to others just by wishing it, he's likely not in too much trouble.) (etonline.com)