Expecting the Unexpected (Diabolik Lovers x Vanitas! Male oc)

(A/N: Greetings my dear reader!
This fanfiction is inspired by another fanfic I read. Make sure to read their fanfic.
Its called 'They Can't Bite' by '@JustAGhostyGhost'
It is great.)

Vanitas, formally known as Akira Tsukumo is an average human, who was experimented on since he was just a child. Saved and bitten by the vampire of the blue moon he inherited his name and the Book of Vanitas from the infamous vampire. The vampire of blue moon told him to stay at a church and he did. The church accepted him and let him stay. There he met Yui Komori to whom he soon got attached and they became inseparable. Vanitas was a troublemaker because of which many times he was kept locked in a room without food as a punishment but Yui was always there for him no matter what.

One day Seiji Komori told Yui and Vanitas that They have to live with their distant relatives till the time Seiji is on a trip.
What will happen when they arrive at their 'distant relatives' house? Well more like a mansion.
What will happen when they find out the secret about the people who live there?

(Warning: I haven't watched diabolik lovers nor vanitas no carte. I am writing this after reading as much fanfic as I can so the characters might get OOC.)