Hatsui, also known as Zara Erutai, is a Genbu Celestial Warrior born under the star Encampment. His parents were healers, and he inherited unique abilities: shooting spikes from his body and forming a protective steel cage or basket around himself and others. He is a shy, timid individual who cries easily and struggles to trust others.
At the age of nine, Hatsui lost his parents and was left with significant debts. When villagers began to bully him, he inadvertently unleashed his celestial powers for the first time, resulting in the deaths of many people. Despite acting in self-defense and having no intention to harm, Hatsui fled his village and isolated himself. Later, a woman named Fen found him and became his friend. However, when Takiko and Tomite arrived to locate Hatsui, it was revealed that Fen was an assassin tasked with eliminating the Genbu Celestial Warriors and their priestess. After rescuing Hatsui from Fen, he became the third Celestial Warrior to join Takiko's group.
