Harry Knowles has well represented a huge portion of the nerd community for a long time now and recently reported on a rumor released by Edgar Dawn. Before I dive into the rumor, I want to point out that I've not heard the name Edgar Dawn before and in doing a quick Google search, I am not finding very much. Harry Knowles pointed out that this was a "big huge rumor" and claimed he believed the rumor is just a "best guess".
The rumor is in the form of a synopsis for "Avengers: Infinity War Part 1", which would be a huge scoop and/or huge problem. Harry Knowles has been pretty loyal to his scoopers as well as those he interviews, and yes, even to a fault. Sometimes I'll read a review from Harry after he's interviewed or had contact with someone who's a big player in the project and it will be obvious to me in his review that he's puffing it up more than it needs or warrants. Having pointed that out, I am not sure how to take a scoop like this.
The rumor is that Adam Warlock and/or his alter ego Magus will be playing a main role and Thanos would be taking a back seat. It was said in this rumor that Magus would be the character who would be collecting the infinity stones to complete the gauntlet and then create evil copies of various heroes to perform his grand plan.
In terms of the first Guardians story, we were told Peter Quill's father was an "angel" in the eyes of Quill's mother and an "a**hole" in the eyes of Yondu. Could Adam Warlock and/or Magus fit these descriptions? It's possible but unlikely. I'd rather bet on Starhawk, an original team member. I find it harder to think Adam Warlock would be introduced and rushed into the current story with just a couple of films to go before reaching "Avengers: Infinity War Part 1".
Unlike many Marvel geeks I'm sure, Adam Warlock is one of my favorites, so I'd hate to see him not get a proper introduction.
If Adam Warlock is introduced, I would assume he's not going to be thrust into the role of villain as Magus until after the Thanos story is done. Harry Knowles sites Production Weekly as a source continuing speculation that Adam Warlock/Magus would be factoring into the storyline for Infinity War.
When are we going to get Beta Ray Bill? Adam Warlock? Quasar? Bug? Nova?