Will other vampires attack me?

Since I'm a vampire, will other vampires attack me or be friendly to me?

Solution 1:

The hostile vampires will still attack you, as if you're a non-vampire. See the UESP wiki article about vampire types, to see which kinds of enemy vampire NPCs these are. Generally, these non-named vampire NPCs don't discriminate between vampire and non-vampire player characters. Named vampire NPCs' hostility towards you will depend on their respective related quests and your disposition towards them.

Also, see the list of Hostile Encounters at UESP wiki. Notice that all of the hostile encounters with vampires will still have vampires attacking you even if you're a vampire yourself.