I will prolly sound cliche af but I'd go for Remilia. I dig that vision of synergy with her as a human since she's in need of those blood doses (I'm type 0 so I'm a perfect donor). That's all there is to it. I'd fancy her swim suit version like in this art since I'm a man of culture and I'm keen on loooong walks with her during the sunset. I'd also enjoy her bites on my shoulder during sexual intercourses. I'm a sucker for vampire princess ladies.