From the Start: The Strongest Spirit, Armigael

An ordinary boy named Zedu receives a mysterious feather on his birthday, only to be caught up in a deadly pursuit. His amnesiac mother exposes a hidden power of thunder to protect him, or perhaps it? Guided by the feather, he flees to the otherworldly realm of Tempura. In this world, where Fragment Masters and spirit beings coexist, Zedu discovers that the mark on the back of his hand is connected to Amilgall, the supreme spirit being of legend...