Totally human, I swear!
Out of my characters, here are some possible candidates and things to know about how the ship might play out.X doesnt have preference in gender, but he would go after someone who can give him power- like a werewolf, vampire. mage, someone with lots of money, etc.
Fenris- Moderately rich. Strong sense of duty to partners and pack members. Will not settle down with anyone who doesn't agree to convert to Lycanthopism and werewolfry. Whether they seek out X, or X seeks out them, doesn't matter much to me.
Knott- Could possibly develop a crush on X, and indulge it mostly because of X's effect on their self-esteem. It doesn't even necessarily have to be a completely positive effect, since Knott has issues with their self-esteem to begin with. Whatever you have planned for X's character development could possibly contribute to Knott's eventual acceptance of their Vampirism as a neutral trait.
Finbar- I could kind of see how this would start, even though things working out for them would be a long-shot. The power X could be after in this case would be Finbar's aptitude for a particular type of shape-changing spell, being the type that can potentially change one's voice and features enough not to be recognized by those not notified of the change, persistent enough that only certain types of magic and magic-cancelling means can undo it. Of course, the fact that Fin can't really keep his head on his shoulders might be off-putting.