You are sent by the church to be a new sacrificial bride after Yui became a vampire and Ayato's wife. As much as you love your faith you were happy to leave your current residence there. They had corruption at the part of the church you were staying and even though you lost faith in them, you didn't loose faith in God. He had a plan for you and you were going to fulfill whatever it was.
The Sakamaki household definitely surprised you, but you knew with these broken men (or should I say vampires) maybe your purpose was to save one of them from despair and loosing the last bit of humanity you know they have in them. If there is one other thing you have faith in other than God, it is the ability to find redemption.
So obviously since it's Laito WARNING! Sexual content will probably be in this.
Also I just wanted to say there probably won't be that many chapters. It's funny, Laito is actually one of my least favorites but I came up with this idea for him that I thought was good and might make me or others like him better (Sorry if it's a little OOC). If a story has potential it should be written even if you sort of dislike the character!