B't
A B't (pronounced "beat") is the ultimate form of artificial intelligence mechanoid (they are NOT "robotics" since in the Machine Empire, "robot" are considered obsolete terminology that has been replaced by much more modernized terms such as "mecha" and of course the terms "B't" itself) designed for fighting - the B stands for Brain, Blood, Bravery and Battler. They have different forms and powers, usually based on mythological creatures. The B't's source of power is a device called BreakHeart, which is fueled by human blood. Once the BreakHeart is inserted into the B't's body, it creates a link between the blood donor and the B't. A B't is also outfitted with The Guard System, which protects its donor from various dangers and environment changes, such as volcanic heat, the crushing pressures beneath the ocean, or even the depths of space. However, the donor must be in physical contact with his or her B't for the system to work for them. Teppei is able to manifest a suit of protective armor called Battle Gear, through use of the Messiah Fist. This has the additional benefit of activating the usually dormant wings on X's sides, enabling him to reach even greater degrees of speed and mobility.
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