You're a vampire who's been killing people in a village for years and nobody knows it's you. Until one day a group of 'travellers' visited the village to help. They caught you, but instead of killing you, they compromise. You never attack humans again unless it is necessary and continue to travel with them, in contrast, one person of the group gives you their blood for you to survive. And that was Kase Morosine.

"Kase, I need your blood. Please." I pleaded him

"Fine, come here." He smirked