You, a male human was killed by your own family..you came out as ghost and a demon came and promised you revenge however in exchange you’ll have to stay with him forever

You accepted, but it was all a trick..he erased your memories and took you to his castle..

You are called Two..and you are not allowed to leave his side..it’s been 5 years since that day..

In the throne room “How are you doing Two~?”