Murtagh and Thorn

After Murtagh had been taken away from The varden by the Kull they tried to find him but they had no luck and came to the conclusion that he had died. Well during the battle of burning plains Eragon encounters another Dragon rider that was not Oromis, or Glabtorix himself. IT WAS MURTAGH. If you know anything about these books you would think that theres no way. But there is the Kull took him to Glabotorix and one of the Dragon eggs hatched for him and he named that Dragon Thorn. They were trained and then sent into battle to fight and capture Eragon. Murtagh is successful in defeating Eragon but show Mercy to his brother and does not take him to the dictator king. Murtagh and Thorn may have won that round but I'm not to sure they will when the next one.