Demonic Transfussion is form of jutsu commonly used by the Demaru Clan. Orginally "Demonic Transfusion" was a Jutsu that was unnamed, it originated in Juugo's clan. Long before Juugo was even born another clan shared similar abilities, both clans joined as one, but soon they split up. Most of the cross-breed children eventually formed the Demaru Clan. They had more control over their powers than any before them, they were practically the strongest Shinobi out there. However they were all or most too kind hearted. They eventually joined the Leaf Village where ninjutsu specialists helped the Demaru gain even more control over their powers and that's how the Demonic Transfusion Jutsu was made.