Blood Transfusion is an ability for Yokai to use their fangs to inject their blood and yōki into another person. This ability has been usually used on Humans when they are in a weakened state. When blood is injected it will heal them, give them power, and turn humans into Yōkai. The only humans that have been injected are Hokuto Kaneshiro and Tsukune Aono. Both of them are now Yōkai.