His name is Kurt Hugo Forrester, he's a vampire MD, an old and a bit distant friend of her family. They usually don't interact untill later in their respective stories, as neither of them considers the other to be fitting company. He comes from an arosticracy, though his parents and little sister died when he was small child. His "older brother" adopted him and later turned into a vampire when he was dying from sickness, and Kurt resents him for it. He's a bit mysterious figure, a man closed in his shell with a flair for the theatricals and drama, torn inside between the want for love and true companionship and fear of being abandoned and hurt, tormended by his hunger and robbed of humanity. There is not many he allows into his inner circle and even less he allows to see his true fragile self. He's also in an on-and-off (very tumoltuous) relationship with his favourite student. A complicated and tragic character to say the least.
When he and Salva met again at his vampire manor both of them didn't even consider falling in love. For him she was a naive plaything meant to be broken, and for her he was a way to get a bit of independence and harmless fun. Needless to say she got attached way too quickly to his damaged self and Kurt is struggling to accept his jelousy and attraction is not only phisical.