Travel back in time, 2000 years ago, when the world was not only inhabited by humans, animals, and plants, but also by mystical beings known as the "MYTH." These entities were born with supernatural powers, making them immensely strong and powerful. However, their strength became a source of fear for humans, who believed that the MYTH posed a threat to their existence. Consequently, the decision was made to eradicate this race entirely, to make them extinct. Humans developed a technique to imprison the MYTH, sealing them in a magical metal, which would transform into a pendant. These pendants, known as "SIGNIA,"

Fast forward to the present day, and the seal begins to weaken, The Signia has the power to choose a worthy person to enter into a contract, granting them supernatural abilities and the authority to release the Myth from its seal. there's a catch - upon release, the Myth's organic form is lost, and it transforms into a formidable metal mecha.