Trouble@Vampire! ~Ano Ko wa Ore no Goshujin-sama~

Ritsu is a new teacher at a prestigious ‘classical’ all-girls school. One day, he saves his students by protecting them from some magic, but ended up getting severely hurt. When he woke up, he saw a girl named Shion, who actually is a vampire. She called him her servant since she had bit him to save him from death after he had lost too much blood.

[From Hau~ Omochikaeri!]