asian drama title plz help?

Its bout teacher + student romance but not like they kiss or anything.

about a male student & female teacher they fall in love i think it was listed as that

but these to know each other since they where kids how ever boy lost his memories of her and was turn into a vampire.

but refuse to drink blood he does not remember his friend who now his teacher


all i remember in end he vanishes into thin air

any ideas


i've remember He then slowly remember his friend and his vampire master keep trying to make him drink but refuse 2 make friends at school i think he move back in with his family who cant believe he did not age