Could be useable character.
According to the IC wiki:
Arva was an Elf and a Dragon Rider. He was the brother of Naudra and the owner of Támerlein. His dragon's name is unknown, though it is known that it was a green dragon.
When Galbatorix and the Forsworn attacked Ilirea, Arva and the other Dragon Riders attempted to defend it. He and his dragon were defeated and mortally injured by Kialandí and his dragon. In his dying moments, Arva gave his sword Támerlein to his sister. She used it to defend herself from the Forsworn and fled the city with another Dragon and Rider. Naudra later died from her injuries. Támerlein was kept as a treasure by her mate, Fiolr Valtharos. Even though Eragon requested to simply borrow the blade, Fiolr was delighted that Eragon would not be able to use it because Fiolr treasured the blade so much. Later, Támerlein was given to Arya and Rhunön fixed it to fit her better.