Well, this certainly seems like the start of something. As Rich Johnston points out, Jim Starlin shares an early image of Thanos on Facebook, and goes out of his way to point out (twice) that the character existed before he went to Marvel:
This is probably one of the first concept drawings of Thanos I ever did, long before I started working at Marvel. Jack Kirby’s Metron is clearly the more dominant influence in this character’s look. Not Darkseid. Both D and T started off much smaller than they eventually became. This was one of the drawings I had in my portfolio when I was hired by Marvel. It was later inked by Rich Buckler.
Legal Eagles, does this mean that Starlin has a claim to ownership (or part-ownership) of the character? He clearly wasn’t created as work for hire. And if so, what could this mean for Marvel’s future plans for the character within Avengers movies and the comic Marvel Universe…?