The upcoming "Captain America: Civil War" is looking like it should be called "Avengers 2.5" as it will feature almost all of the major superheroes from the first Avengers film. Captain America, Iron Man, Hawkeye, Black Widow and even the Hulk are all making appearances in the movie alongside a slew of other heroes. There is, however, one major omission -- Thor.

The fact that Thor is not in the new movie calls into question whether the hero from Asgard might be on his last legs in the Marvel Cinematic Universe.

We have talked about it before -- someone has to go at some point. There is simply no way that Marvel will be able to balance a movie that features the original Avengers, the Guardians of the Galaxy and the other heroes that will inevitably be added. As the recent "Avengers: Age of Ultron" showed, too many characters limits what you can do with them in a two and a half hour film. The characters must be cut down whether by death or other means.

Thor seems to be the target as of right now, missing out on the Civil War. Actor Chris Hemsworth's contract is seemingly close to expiring and Disney might not be keen to re-sign him and prolong a superhero franchise that has not yielded the best of results. Neither "Thor" movie cracked the top seven on Marvel's all-time domestic box office to date. "The Dark World" barely cracked the $200 million mark.

Internationally the films did better, landing in sixth ("The Dark World") and ninth ("Thor") on the current list of 12.

Critically the first film got solid reviews while the second movie was panned and received some of the worst marks for any Marvel film to date.

If the upcoming "Thor: Ragnarok" fails to ignite audience imagination, then it might be time for Marvel and Disney to retire the character for a while until the roster is whittled down a bit and the cycle starts anew.

That plan may already be in the books.