That is these character may be used anyway anybody wishes without the need for premission and without ever paying for their usage expect for copyrighting them, trademarking them, or selling them.  Even though, the characters may not be sold; the products you put in may be sold so long as you have permission to sell the respective products.

Just a few examples of what may be done with them out of an unlimited number of possibilities: Create a new game based around them which you may sell, Add them into an official episode of a t.v. show, created hentai pictures.

Brian Lowpass
He is able to lead any team you put him in charge of but practually useless in most solo missions.  For example he would make the combined forces of Deathcry, Dr. Druid, Darkhawk, Squirrel Girl, Rage, and Mockingbird actually able to work together and complete Avenger missions.