When Nasuada gets captured by the Empire, she withstands an ungodly amount of torture by Galbatorix himself. Her only solace is an unexpected ally: Murtagh. He heals her after her torture sessions, talks to her, weeps for her pain, and explains that he was the one responsible for not only her capture, but also her survival. Galbatorix was going to send the Black Hand to kill Nasuada, but Murtagh convinced him to capture her instead. He contacts her with his mind and warns her whenever Galbatorix is about to make her hallucinate. He holds her as she cries after a particular Nightmare Fuel-tastic torture session involving burrowing worms and promises her he'll figure a way to get her out of there. During Murtagh and Eragon's duel, the only reason Murtagh is so furious is because if he'd just waited another day, Murtagh was going to get Nasuada out. And the only way they ultimately defeat Galbatorix in the end is because Murtagh turned on him because his true name had changed- for her. Definitely a CMOH for Murty, and officially confirms (sort of) the Murtagh/Nasuada ship.
Eragon entering Urgals and dwarves into the bond with dragons, so that all four main races of Alagaesia can become Dragon Riders.