Fated Mate for a Vampire

Xander's vampire master is dead, making him a free familiar. The only kicker is, most male vampires die shortly after their master's pass, but Xander has never been normal and he is not about to give up his newfound freedom. However, it comes with side effects. He can no longer use his powers with the same control he once could. The souls he curses into objects now have their own free will. Meaning it might be best not to use his powers anymore and hide away his powerful but insane cursed sword.
A decade later, he's summoned to the vampire capital, to attend the coronation of his master's son. Turns out, everyone is wanting his cursed sword, and the only ally he can trust is an Empress from another Vampire Kingdom who is obsessed with Xander and convinced he is her fated mate. Which is impossible. Only born vampires gets fated mates, not turned ones. Evidence keeps piling up making it undeniable that she is his fated, and even if she's not, she is the only one who can give Xander back the power he once had. A power he could use to get revenge on all the vampires who have wronged him and the humans.