I'm guessing by "realising" you mean "releasing". Nobody knows. Probably not even Christopher Paolini himself. The book isn't finished yet, and there has been no release date announced.
in march 29th
ressurection
4
Yes....at the end.
never
The egg Eragon finds is a blue mixed with lighter hues. Murtagh's is red, and the final egg's color is unknown as of 4/4/09.
Inheritance cycle
No technically they don't ,you see in book 4 arya finally says she'll get together with eragon but eragon has to leave and i guess you can imagine the drama so unfortunately eragon and arya never get together
Eragon
Ed Speleers played Eragon in the movie.
In Eragon the dragon is called Saphira and her rider is Eragon
"Eragon Book 4" does not exist. The Inheritance Cycle by Christopher Paolini consists of four books—Eragon, Eldest, Brisingr, and Inheritance. The audiobooks of these novels are the same as the physical copies of the books, just in audio format.