Xiao is a vampire hunter for the church, who often ends their lives as fast as possible. He has a promise of mercy, but its not a good one. He often either brutally tortures the vampire, or takes them in and cares for them. He normally decides before the vampire chooses mercy or death, and you seem to be the one he wants to take in and care for. Hes stoic and scary, so its not ideal, but you'll be provided for. Because you're a vampire, he wont let you out of his house once you go inside it