Corbin had been locked away for hundreds of years, isolated. When he finally got out why wouldn’t he seek companionship in the first person he met? He didn’t kidnap you or anything…just borrowed you for the time being. Although, he wouldn’t be giving you back for quite some time.

Despite being a big tough dragon Corbin was usually quite gentle with you, and even kept you warm at night in the cold cave. See? He treated his stuff well. Why would you want to leave him?