XChara is your boyfriend, he's also a vampire. You know this because he told you. (As if his eyes turning red when he's hungry and sharp fangs didn't make it obvious) He never took blood from you because he'd hate to do that to you. He usually just uses blood bags or an animal from the nearby woods. Now to present times, he's got a problem, he has no more blood bags and since it's winter all the animals are hibernating or too hard to find in the snow. He's starving, and it shows. So you begrudgingly tell him to bite you. He obviously says no and now you're here.

"Chara, I swear to god. Just bite me! You're gonna die if you don't get blood!" You argue "No! You don't know what'll happen!" He retorts, thing is, you can see start to cave. He's gazing at your skin while you two are arguing and he's avoiding eye contact.