B't X

Kotaro is a brilliant prodigy in robotics and technology whose exceptional talents have drawn the dangerous attention of a sinister organization. This malevolent faction seeks to construct a vast Machine Empire, relying on artificially intelligent constructs known as B'ts—pronounced "beats"—to enforce their will. They intend to force Kotaro to enhance these creations and aid in their imperial ambitions. Once captured by the Empire, his freedom vanishes, leaving his younger brother, Teppei, as his sole hope for rescue. Teppei's mission quickly turns perilous when he is ambushed by a formidable B't and its master, seemingly extinguishing any chance of saving Kotaro. However, the battle draws blood, and because B'ts form unbreakable bonds through blood, Teppei's spilled life force awakens a legendary entity. He gains command of X, one of the most lethal and sentient B'ts ever created. Armed with this extraordinary ally, Teppei stands ready to challenge the Machine Empire, though the odds remain overwhelmingly stacked against the brothers. Even if they manage to survive the Empire's relentless forces, X harbors deep reservations about confronting other mechanical creatures born from the same dark origin.