Blood Transfusion is a Yokai ability to use their monster fangs to injected their blood and energy to the another person.This ability it's been usually use to the Humans when they are in a weakend state,when blood is injected it will heal them,give them a power and turn into a Yokai.Known Humans has been injected they are Hokuto Kaneshiro and Tsukune Aono,both of them are now Yokai.
Side Effects and Degenerations
If Human is injected blood so many times then he/she will get side effect from the inside and dying but if Human is able to survive and endure this effect then Human's body will degenerate into another Yokai being.Such examples are Hokuto that have been turn into a multi-limbed Skeletal Beast due the degenerative monster blood from Kiria Yoshii and Tsukune who was turning into a Ghoul a mindless killing machine due the degenerative blood from Moka Akashiya.