Hi,

On my newest character, a female Orc battlemage necromancer vampire, I joined the Empire because on my first two chars I was a Stormcloak and I wanted to experience the Empire side. But now I think if it makes sense lorewise for an Orc necromancer who's also a vampire to join the Empire since she cares only for feeding and experimenting with the undead.

It is common for Orcs to join the Legion, at least over the last 200 years. Most would be smiths and warriors, but I don't see why they wouldn't accept someone who has magical training. The Vampire thing would be more controversial, but that is something one is expected to hide anyway. And with your motivation, you can pretty much justify joining either side.

Also note that (Nibenese) Imperials are traditionally more tolerant towards necromancy.

Yeah, I remember dialogue from Morrowind talking about the romantic tradition of noble vampires within the Empire, who rise through the ranks of the nobility. Kind of like a early reference to Janus Hassildor or Sybille Stentor.

Also, necromancy is legal in the Empire. And the Empire even http://www.imperial-library.info/content/preparation-corpsenecromancers. It was the division over whether necromancy should be legal in the Mage's Guild that ended up destroying that organization. When the Mage's Guild disbanded, it split into the Synod and College of Whispers. The Synod is anti-necromancy, while the College is pro-necromancy and allows it within its ranks. The College of Winterhold also allows necromancy in its ranks.

And like Tdroid mentioned above, Orcs have a long history in the legion, so I see absolutely no problems with a orc necromancer working for the Empire. Just keep your vampire identity a secret, okay?