Yoichi is an average-height boy with medium-length brown hair and large, dark green eyes that give him a youthful appearance. In his school uniform, he wears a gray gakuran with a light blue design, fitting in with his peers.

As a member of the JIDA (Japanese Imperial Demon Army), Yoichi wears the standard uniform, which consists of a long-sleeved black coat with light green details, including shoulder epaulettes. The coat features a brown Sam Browne belt diagonally crossing over his right shoulder and two rows of gold buttons on the front. Completing the look, he wears white gloves and a white web belt with a gold waist-plate. His uniform trousers are paired with black boots that rise over the leggings, and he is often seen wearing a cap and cape, which adds to his imposing military appearance.

Yoichi is a kind-hearted and good-natured individual, often seen as the peacemaker of Shinoa’s squad. He is generally unaggressive and initially struggled with standing up for himself, often running from bullies rather than confronting them. However, this passive nature shifted as he matured and began to take responsibility for the safety of those around him, particularly after the tragic loss of his sister. His desire for revenge was not fueled by hatred, but by a sense of obligation and duty, deeply rooted in the cultural expectation of seeking vengeance for a loved one.

As Yoichi’s character developed, he became more self-reflective and gained a deeper understanding of his own feelings. His concern for his friends and his innate kindness pushed him to tackle challenges he had previously feared, like fighting vampires, and to seek out the strength to protect others. This sense of duty led him to willingly acquire a cursed gear, and through his perseverance, he overcame the demon that threatened to control him. Rather than changing his inherent good nature, Yoichi found strength by embracing it, allowing his bond with his cursed gear to grow stronger.

Over time, Yoichi grew more confident in himself, especially as he bonded with Shinoa’s squad, whom he began to see as his family. His supportive and nurturing personality made him the glue that held the group together, and his calming influence often diffused conflicts between the more hot-headed members, such as Yuichiro and Kimizuki. Although Yoichi still dislikes conflict, he has become a fierce and reliable ally in battle. His archery skills, paired with his ability to analyze situations and provide tactical support, have proven invaluable. He has gained confidence in his combat abilities, even effortlessly taking down multiple Horsemen on his own.

Despite the growing strength in his resolve, Yoichi remains humble and never hesitates to fight for his friends, even in the face of overwhelming odds. His transformation from a nervous and unsure boy into a confident protector of his squad highlights his growth and his deep care for those he considers family.

Yoichi’s backstory is marked by trauma and loss. After the apocalypse that wiped out 90% of the world’s population, only children under the age of thirteen were left alive. Yoichi, along with his older sister, was one of the survivors. During a pivotal moment in his childhood, Yoichi was told by his sister, Tomoe, to hide under the bed as a vampire arrived to gather children for livestock. Yoichi, in a moment of fear and helplessness, froze and was unable to do anything to save her. He watched, powerless, as his sister was killed by the vampire, an event that would haunt him for the rest of his life.

This traumatic experience shaped Yoichi’s early personality. For a long time, he carried a heavy burden of guilt, believing that he should have done more to protect his sister. The loss deeply affected his sense of self-worth and his initial hesitancy to act. However, over time, Yoichi’s desire to protect those around him grew stronger, and he found a new sense of purpose in the bonds he formed with his squad and the people who became his new family.

Yoichi’s powers and abilities make him a formidable member of the squad. He is noted for his exceptional curse control abilities, which give him a surprising level of stability when facing demons. His ability to withstand and resist demonic influence is notable, with Sayuri describing his resistance as surprisingly high. Additionally, Yoichi was almost completely unaffected by Mahiru-no-Yo’s powers, showcasing his unique capacity to remain stable in the presence of dangerous supernatural forces.

Yoichi’s primary weapon is his cursed gear bow, Gekkouin. This weapon can be conjured at will and takes the form of a large black archery bow with two fluorescent green circles. The bow fires long arrows with explosive impact, capable of piercing through and annihilating enemies. Yoichi can fire multiple arrows at once, each of which can be redirected to alter their trajectory and strike different targets, such as the powerful Four Horsemen of John.

His weapon’s manifestation power allows him to summon a massive green and black bird-like missile, a projectile with tremendous destructive capacity. The more power Yoichi draws from his demon, the more arrows he can fire, making him a dangerous force on the battlefield. His ability to rain down multiple shots and annihilate vampires makes him an invaluable asset to his squad.

Yūichirō Hyakuya
Yoichi and Yu share a close bond, with Yoichi often admiring Yu’s determination and strength. Their friendship is built on mutual trust and a shared goal of protecting others.

Shinoa Hīragi’s Squad
Yoichi forms strong bonds with his squadmates, including Shinoa Hīragi, Shihō Kimizuki, and Mitsuba Sangū. His supportive and kind nature helps maintain morale within the group.

Tomoe Saotome
Yoichi’s older sister, Tomoe, was killed by vampires, motivating his desire for revenge and driving his decision to join the Japanese Imperial Demon Army.

Yoichi Saotome is a vital member of Shinoa’s squad and an integral part of the Seraph of the End narrative. His journey from a shy and gentle soul to a confident and capable fighter underscores the themes of growth, resilience, and the power of teamwork. Yoichi’s dedication to protecting humanity and honoring his sister’s memory make him a compelling and relatable character, contributing significantly to the emotional depth of the series.