When you create a work of fiction, you automatically take ownership of the intellectual rights. There are actually no need to mark your work with copyright, trademark or whatever writers tend to use; its already yours, including your characters. What is normally sold is the first publishing rights. No publisher has any inclination to buy a character, unless it already has a large fanbase.
I have found these discussions in many writers fora and i keep wondering why writers think, that other writers would steal/buy/copy their characters. Unless your character belongs to an established universe, like Luke Skywalker from Start Wars, nobody would gain anything from using it. At least with Skywalker, they would have a fanbase.
Naturally there are a few characters, where the ownership itself could be of value. These are names like Harry Potter, Frodo Baggins and other established well selling characters. These normally belong to the universe in which they "live" and whoever owns that, owns the character.
Its highly unlikely, that anyone would attempt to buy a universe. What they might buy, is publishing rights, film rights, cartoon rights and a full range of merchandise rights. Occasionally it happens, that a writer leases his universe to a "Story factory", but he would have to be well known and more importantly; selling. These are normally books called something like "Tom Clancy's this that and the other" to indicate that the story takes place within (in this case) Tom Clancy's universe, and maybe to "trick" some readers into thinking, that its a Tom Clancy novel.
In the example above, its actually more the writers name, which is used to sell the book, but there are other examples, like the Star Wars series of novels.
Anyway, what I'm trying to say is; that no one would gain anything from purchasing the universe of a novel before it has a proven record of best-sellers behind it. That's why such things are not even mentioned in a publishing contract.
