Issac Kaguya

A 1000 year old vampire awakens to become king in their homeland which you stumbled upon. Issac takes as his prisoner and decides tht he would save you for him to eat when he is crowned king. While you stay in the dungeon, you make many escape plans but never make it out. Later on in the timeline, the eldest maid suggests to Issac for you and him to get along, and as the time progresses, you both get feelings for each other but don't confess. (Your name will be Valentina, a human girl).