Guren Ichinose is a tall, young man with striking purple eyes and medium-length black hair. His hair is typically parted in the middle with the bangs hanging over his forehead, though it is occasionally slicked back during battles to keep it in place. Guren’s hair often appears slightly tousled, giving him a more rugged appearance.

His attire consists of the standard JIDA uniform, a long-sleeved, double-breasted black coat adorned with two rows of gold buttons down the front. The coat features red details, including shoulder epaulettes, gores at the bottom, and stripes on the sleeves, making it a distinctive and highly decorative military garment. Additional elements of his uniform include gold aiguillettes and a white fourragère worn on his right shoulder, all of which highlight his high rank and status. At the center of his collar, he wears a stylized cherry blossom decoration pendant, accompanied by two bars with a unit insignia medal on the left side.

Guren also wears a pair of white gloves, a black-and-white striped armband on his left arm, and a black and white web belt with a frog for his sword, secured by a gold waist-plate. His trousers are part of the uniform, with two white belts wrapped around his left leg, and he completes the look with black shoes.

When Guren is in his Namanari state, his eyes retain their violet hue but are surrounded by a bright red ring, reflecting his transformation into a more demonically influenced form. This change symbolizes his increased power and the loss of his full control, marking his transition into a more dangerous version of himself.

Guren Ichinose is a wise and determined leader who values teamwork, cooperation, and the bonds of friendship, believing these qualities to be essential for the survival of humanity in the face of demons and vampires. Although he often pretends to be lazy, Guren is incredibly hardworking and committed to his goals. He has a strategic mind, keeping many secrets to himself, and is skilled at lying and manipulating situations when necessary. His strong sense of honor and emotional connection to others sometimes conflicts with his leadership responsibilities, particularly when dealing with the harsh realities of war and survival.

While Guren’s leadership is driven by a deep care for his comrades, this emotional attachment is also his weakness. He believes in the value of love and friendship, but this sometimes hinders his ability to make objective decisions. For instance, when Yūichirō Hyakuya first tried to join the Moon Demon Company, Guren refused to accept him until Yū made friends, underscoring his belief that teamwork and mutual respect are paramount. Despite being viewed as weak for his emotional nature by figures like Kureto, Guren’s ability to connect with others is a strength that allows him to inspire loyalty in his squad.

However, Guren’s personality undergoes drastic changes when he becomes possessed by his demon blade, Mahiru-no-Yo. Under Mahiru’s influence, Guren becomes ruthless, willing to sacrifice his comrades and use them as pawns in the Seraph of the End experiment. In this state, Guren shows no hesitation in killing both vampires and humans alike if it serves his goal. While he remains aware of his actions, he loses much of his emotional control and becomes detached from the reality of his actions, especially when confronting the people closest to him, like Yu and Mika. Guren’s ruthless nature in this state contrasts sharply with his usual leadership style, as he is willing to use extreme measures to achieve his aims, regardless of the cost.

Despite the violent tendencies exhibited by his demon side, Guren still holds onto fragments of his former self, which becomes evident when he interacts with people like Mika and Shinya. His detachment, however, is not without consequences. Guren’s Namanari state, where his demon side is in control, leaves him cold and indifferent to the pain and suffering of others. While capable of rational discourse, Guren’s moral compass becomes skewed under the influence of Mahiru-no-Yo, and he becomes more inclined to take violent, extreme actions without hesitation. Even in this state, Guren still maintains a deep connection to his past, particularly to the goals he shared with Shinya and Mika from their childhood.

Guren’s dual nature, torn between his human emotions and the demon that lies within him, makes him a complex and conflicted character. His struggle with this inner demon drives his actions throughout the story, making him both a formidable leader and a tragic figure, constantly on the edge of losing himself to the very powers he wields.

Guren commands the Vampire Extermination Unit’s Moon Demon Company, leading humanity’s fight against the vampire threat. His leadership is instrumental in organizing missions and coordinating strategies during critical battles.

Guren prepares both the Guren Squad and Shinoa Squad to defend Shinjuku against a large-scale vampire invasion. His tactical expertise and combat prowess play a crucial role in protecting the city.

Tasked by Kureto Hīragi, Guren leads the mission to target high-ranking vampire nobles in Nagoya. This operation highlights his ability to lead large-scale campaigns and his importance in the war against vampires.

Guren’s backstory, explored in Seraph of the End: Guren Ichinose: Catastrophe at Sixteen, reveals the tragedies and challenges that shaped his current motivations and decisions. His connections to the Hīragi family and his complicated relationship with Mahiru Hīragi add depth to his character.

In his possessed state, Guren Ichinose exhibits extraordinary physical prowess granted by his demon weapon, Mahiru-no-Yo. This power significantly enhances his speed and strength, allowing him to move at remarkable speeds, although his movements are ultimately countered by the third progenitor, Krul Tepes, who pins him down in defeat. Despite this, Guren’s enhanced physical capabilities allow him to overpower even someone as powerful as Mika, a vampire who had recently ascended to a true and complete vampire state. Guren’s strength is such that he can effortlessly lift Mika by one of his feet and hurl him into Yu, knocking them both over. Additionally, he proves to be highly skilled in close combat, able to fend off both Yu and Kimizuki simultaneously with ease, demonstrating his exceptional combat abilities even when handling multiple opponents.

Guren’s abilities with Mahiru-no-Yo go beyond physical strength; the weapon also grants him the ability to summon destructive power. He can create a red whirlwind enveloped by a thin layer of crimson demonic aura, which he launches at his targets with devastating effect. This power is potent enough to demolish concrete walls and temporarily incapacitate those in its path, including Yu, Shinoa, and Mitsuba. Furthermore, Guren can channel his weapon’s power into a concentrated destructive force that tears through his opponents, even when they are capable of fighting back.

Mahiru-no-Yo undergoes significant transformations in Guren’s hands. When he speaks of drinking the blood of humans, demons, and progenitors, the weapon changes its color, shifting from black to a deep red. This transformation is akin to the power exhibited by first-class vampire weapons, signaling the weapon’s full potential being unleashed. This change is a testament to Guren’s control over Mahiru-no-Yo, as he can alter its appearance and power without the aid of external talismans or rituals. This transformation further cements Guren’s dominance in battle, enabling him to wield immense power with ease.

As Guren taps deeper into Mahiru-no-Yo’s power, his abilities grow exponentially, and the line between his humanity and his demon side becomes increasingly blurred. His overwhelming strength and newfound control over his weapon make him a formidable force, capable of taking on powerful enemies and even overpowering his own comrades when the demon side of him takes control. However, his transformation into a Namanari, while granting him immense power, also brings a deeper detachment from his emotions, further complicating his identity and motivations as a leader and a warrior.

Shinoa Hīragi’s Squad
Guren acts as a mentor and guide to Shinoa’s squad, preparing them for high-stakes battles and missions. His dynamic with Shinoa and her team reflects his role as both a leader and a teacher.

Mahiru Hīragi
Guren’s past romantic relationship with Mahiru deeply influences his actions and decisions. Her descent into darkness and ultimate fate remain a source of pain and guilt for him.

Kureto Hīragi
As part of the Hīragi family hierarchy, Guren follows orders from Kureto but often clashes with him due to their differing ideals and methods.

Guren Squad
Guren shares a close bond with his squad members, including Sayuri Hanayori and Shigure Yukimi, valuing their loyalty and trust.

Guren Ichinose’s leadership, intelligence, and moral complexities make him one of the most compelling characters in Seraph of the End. As a key figure in humanity’s resistance against vampires, his actions and decisions drive much of the series’ narrative. Guren’s dedication to his comrades, his tragic past, and his willingness to shoulder immense responsibility highlight the themes of sacrifice and redemption central to the story. His role as a mentor, leader, and warrior ensures his lasting impact on both the characters and the overarching conflict of the series.