- "...Please...Priestess, stop lying. I know you're lying so that I'll stop worrying! No! Please tell me the truth! Keep fighting it. You don't have to lie just because you don't want me to get worried..."
Hatsui is the second Genbu warrior who joins Takiko. A timid, shy boy born to herbal medicine farmers who finds it difficult to trust others, Hatsui is sensitive, so the Genbu Warrior easily cries. His true name is Zara Erutai (ザラ-·エルタイ Erutai Zaraa) and was born under the star Encampment. Hatsui is from a small town called Tooru, but when he accidentally abused his powers he ran away to hide in the woods. He was found by Fen, an assassin hired by Uruki's father, who used him for her own plans. She put him into a cellar and made him kill wanderers and others saying that they were there to kill him. Even when he finds out about this from Takiko he still thinks kindly of Fen. However upon his meeting with Takiko, Takiko makes him realize his destiny as a Celestial Warrior and he follows her on their search to find the others.
Hatsui's parents died when he was nine-years-old and left behind large debts to pay off. Villagers began to pick on him so he accidentally unleashed his celestial power for the first time and killed many people. Though he had acted in self-defense and he did not have any intention of hurting others, Hatsui ran away from his village and secluded himself. Sometime later, a woman named Fen discovered him there and befriended him. Fen tried to coax him out of the iron basket where he secluded himself, but that was in vain.
However, when Takiko and Tomite arrive to find Hatsui, it is revealed that Fen is an assassin with a mission to kill the Genbu Celestial Warriors and their priestess. He has a hard time accepting it and even shoots needles at them. When Fen tells him to kill Takiko and Tomite, he shoots. He only stops when Takiko realizes that those needles are the pain of his "heart." Hagas appears and kills Fen. After rescuing Hatsui, Hatsui becomes the second Celestial Warrior to join Takiko. Takiko has become a sort of older sister or mother figure to him, and he admires her ability to be both kind and strong. He has great respect for her. He treats Uruki with respect as well, but doesn't quite understand why he doesn't appreciate compliments such as "you're beautiful, too!". He gets picked on by Tomite a bit, in a sibling sort of way and put to do the menial tasks Tomite doesn't want to do. Hatsui seems very comfortable with the quiet Namame, and they've been seen sitting together making little stone statues.
The nature of his powers is not quite clear. He seems able to control and manipulate iron, and can cause it to manifest out of nowhere. With this ability, he can create a circular case of iron to protect himself or others. He's also capable of creating needles that shoot out of his body to puncture his attackers. He doesn't do this often, and usually only occurs if he's very distressed.