Yoriichi Tsugikuni

Biodata

Background / History

Family Life and Loss

After leaving the Tsugikuni family, Yoriichi met his future wife. They lived modestly but shared a warm, loving home. When she went into labor, Yoriichi left to find assistance; a demon killed her and their unborn child before he returned 92.

An ancestor of the Rengoku family found Yoriichi devastated at the scene and contacted the Kakushi. With their assistance, Yoriichi arranged his wife’s funeral. Her grave stood on Mount Kumotori, with Blue Spider Lilies growing nearby 92.

Teaching the Demon Slayer Corps

Yoriichi joined the Demon Slayer Corps and introduced Breathing Styles to swordsmen who had previously fought without them. Rather than requiring everyone to reproduce Sun Breathing, he helped them combine breathing techniques with their existing sword forms and individual strengths. This produced styles including Wind Breathing, Flame Breathing, and Thunder Breathing 92.

His older twin brother, Michikatsu, also joined the Corps. When Michikatsu worried that their techniques would eventually disappear, Yoriichi argued that neither of them was indispensable and that future generations might surpass them 87.

Encounter with Muzan

Approximately three hundred years before the main story, Yoriichi gravely wounded Muzan Kibutsuji. When Muzan split into more than 1,800 pieces to escape, Yoriichi destroyed over 1,500 of them. The surviving demon retained wounds that continued to burn for centuries 2 99.

Tamayo witnessed the encounter. Yoriichi spared her, and they promised to fight Muzan together. She subsequently researched methods of defeating Muzan and contacted Yoriichi whenever she made progress 17 18.

Departure from the Corps

Michikatsu became the demon Kokushibo and killed Sun Breathing successors as well as the Corps’ leader. Yoriichi’s failure to kill Muzan and his decision to spare Tamayo also became grounds for his expulsion 18 92.

The murdered leader’s young son was willing to forgive Yoriichi, and the Rengoku family ancestor pleaded on his behalf. Nevertheless, Yoriichi left the Corps. Its surviving records preserved his portrait but lost much of his history and knowledge of his breathing method 11 92.

Final Duel and Burial

In old age, Yoriichi encountered Kokushibo again. Though extremely thin and aged, he delivered a slash whose speed and power remained equal to those of his prime. The attack nearly severed Kokushibo’s neck, but Yoriichi exhausted the last of his life before he could strike again and died standing 18 23.

Kokushibo cut his corpse in half at the waist, also severing the handmade flute Yoriichi had kept since childhood. Finding the flute brought Kokushibo to tears, and he departed rather than continue looking at his brother’s mutilated body 5 18 21.

Tamayo secretly witnessed the aftermath. After Kokushibo left, she gathered Yoriichi’s remains, built a grave, and continued tending it for hundreds of years 18.

Appearance

Yoriichi had long, dark red hair, a dark red Demon Slayer Mark at the corner of his forehead, and sun-patterned hanafuda earrings. Kokushibo recognizes these features, together with a red haori and an identical face, when he encounters Lin Yoriichi 1 21.

• Hanafuda earrings: Inherited from his mother 21.
• Demon Slayer Mark: A conspicuous forehead marking that remained central to others’ recognition of him 1 21.
• Elderly appearance: Described as little more than skin and bones, without a corresponding decline in the power of his final slash 23.

Personality

Yoriichi was calm and humble about his place in history. He rejected Michikatsu’s belief that their generation’s abilities made them irreplaceable, describing the brothers as merely “two specks of dust in history.” He believed that people following different paths could ultimately reach the same destination 87.

His teaching accommodated other swordsmen’s talents instead of demanding that they master his own style. His willingness to spare Tamayo and cooperate with her against Muzan likewise showed that he could distinguish an individual demon from the enemy he sought to destroy 18 92.

Yoriichi retained a deep attachment to his brother despite their separation and Kokushibo’s transformation. He carried Michikatsu’s childhood gift into old age, keeping the flute until his death 5 18.

Abilities & Skills

Sun Breathing

• Created Sun Breathing, a style the other swordsmen of his era could not master directly 87 92.
• Supplied the foundation from which other swordsmen developed Breathing Styles suited to themselves 92.
• Demonstrated his swordsmanship to Sumiyoshi Kamado, an event Lin recalls while investigating how the techniques were passed down 80.

Exceptional Swordsmanship

• Destroyed more than 1,500 of Muzan’s fleeing fragments during their first encounter 2.
• Nearly beheaded Kokushibo with a single slash at the end of his life 18.
• Retained the speed and power of his prime despite his advanced age and frail appearance 23.
• Left thirteen lasting scars on Muzan and a persistent wound on Kokushibo’s neck 23.

Transparent World

• Possessed the perceptual ability reproduced by Lin’s cosplay system, allowing observation of muscles, organs, and blood flow inside an opponent’s body 1 2.
• Forms part of the abilities Lin must understand more deeply by studying Yoriichi’s life and teaching methods 92.

Demon Slayer Mark

• Bore a distinctive forehead mark associated with his extraordinary combat abilities 2 21.
• Lived into old age despite bearing the mark—an exception that intensified Kokushibo’s jealousy 23.

Bright Red Nichirin Sword

• Wielded a heated blade whose attacks left wounds that demons could not fully regenerate for centuries 2 23 99.
• His original Nichirin Sword later allowed Lin to obtain the complete bright red blade effect, replacing the incomplete effect of his imitation weapon 25 45.

Instruction

• Understood how to teach breathing techniques, not merely how to use them himself 92.
• Helped swordsmen adapt existing Flame, Wind, Water, Thunder, and Stone sword forms into personalized Breathing Styles 92.

Equipment / Items

• Nichirin Sword — His original weapon survives into the main story. Lin retrieves it during the Swordsmith Village events and gains the complete bright red Nichirin Sword effect 11 25 45.
• Sun-patterned hanafuda earrings — Earrings inherited from his mother; their appearance helps Muzan and Kokushibo identify Lin as the supposedly resurrected Yoriichi 1 21.
• Handmade flute — A childhood gift from Michikatsu, carried throughout Yoriichi’s life. Kokushibo recovered it after cutting both the flute and Yoriichi’s corpse in two 5 18.

Relationships

• Tsugikuni Michikatsu / Kokushibo — Older twin brother. His jealousy of Yoriichi’s talent endured after becoming a demon, while the recovered flute briefly revived his human feelings 18 21 23.
• Wife and unborn child — Their murder by a demon preceded Yoriichi’s entry into the Demon Slayer Corps 92.
• Tamayo — Spared demon and research ally. She buried him and maintained his grave while continuing their shared struggle against Muzan 18.
• Muzan Kibutsuji — Enemy whose near-death encounter with Yoriichi left centuries of physical scars and recurring nightmares 2 87 99.
• Rengoku Family Ancestor — Helped arrange his wife’s funeral, witnessed his work in the Corps, and defended him before his departure 92.
• Sumiyoshi Kamado — Ancestor of Tanjiro Kamado who witnessed Yoriichi demonstrate his swordsmanship 80.
• Lin Yoriichi — A separate person whose system reproduces Yoriichi’s appearance and abilities. Lin studies his memories but ultimately chooses to confront present problems through his own methods 1 87 92.

Legacy in the Main Story

Notable Quotes

“Brother, we are not that important.” 87

“Across the vast span of time, you and I are merely two specks of dust in history.” 87

“Those who pursue their path to its end reach the same destination.” 87

“How pitiful, my elder brother.” 87