B't X

Brains, blood, bravery, and a battler: a B’t is made up of each of these, and more. The next generation of robot, B’ts possess individual thoughts, great power, and are powered by one thing: blood. They obey only one person implicitly: the blood donor who awakened them. The Machine Empire has been hiding their creation, planning to use them in their quest for world domination. When Kotaru, a brilliant scientist, begins research along lines that would lead to B't, the Machine Empire kidnaps him to do their bidding. His brother Teppel pursues them, but is wounded in a battle with an old adversary. Beat and bleeding, Teppel's blood ends up wakening B't X, one of the most powerful B't who just so happens to belong to Teppel's teacher. Can Teppel convince X to fight with him and help rescue his brother?