Red

Based on a headcanon from Tumblr (eragonheadcanons.tumblr.com)

Eragon did defeat Galbatorix but was wounded by him in their final battle-a wound that doesn't heal with conventional magic or healing treatments. He lies in a bed in the castle and is proclaimed King, despite not being conscious or consenting. Several months pass and laws are passed under his name, one of which frees every slave in the country. One of the slaves freed comes to the castle to work as a servant instead of seeking an entirely new life and profession. They meet Murtagh, who has stayed instead of leaving and make some sort of impression on him. They are asked to come and help take care of the wounded King.