Is Morzan really Eragon's dad

Actually, No. If you haven't read Brisingr, Stop reading, as this is a big secret you don't learn until almost the end of the book. Eragon's father is (If you can, I suggest you look for small hints of this in the books, Because they are there) Brom. Yep, Brom. Apparently, Brom fell in love with Selena, even though she was married to Morzan. Not even Galbatorix or murtagh knew this. Only Brom and a few select people he told knew about him and Selena. Oh, and get this, Saphira knew, and she didn't tell Eragon! (Oaths stink.)