I'm planning to buy Diablo III for myself. However, I'd like to create a second character for a friend of mine, who is not yet convinced. So I want to let them play that character (in my account) for some time, and if they like it, they could get their own Battle.net account and we could play together.
My question: is it possible to transfer that initial character from my account to their new account, or do they have to start over?