This post is related to the original Skyrim as well as Dawnguard. I'm interetsed in becoming a vampire but I want to be a good one and I have some reservations. It seems the most harmless way of sustaining it is by feeding on sleeping humanoids and thats not ideal, is it possible to have permission before feeding? Can you feed on animals? Can you turn other people into vampires by accident or willingly? Another method I saw is that you can get a blood potion from Dawnguard but to do that I have to join the Vampire Lord and as far as I'm aware he's evil. I guess one way to feed is to wait to get attacked by a bandit and then feed on them.

Without giving away any spoliers is it possible to join the vampires in Dawnguard without being evil and having a secret good agenda? Joining the vampire hunters just sounds boring.