Araki Mataemon is a central antagonist in the story, a legendary samurai of the early Edo period who is brought back from the dead through the dark ritual of the Makai Tensho, or Demon Realm Reincarnation. In life, he was a historical figure renowned as a formidable swordsman and the founder of the Yagyu Shingan-ryu martial tradition, having studied under the master Yagyu Munenori. His mortal existence ended in 1638, allegedly by poison, following his participation in the infamous Igagoe vendetta at Kagiya no Tsuji, a duel in which legend claims he single-handedly cut down over thirty opponents. In the narrative, he is among the first warriors resurrected by the sorcerer Mori Soiken at the site of the Shimabara Rebellion, alongside the Christian rebel leader Amakusa Shiro Tokisada. This act marks him as an early and eager recruit to the demonic army assembled to overthrow the Tokugawa shogunate. As an undead warrior, Araki Mataemon's personality is defined by a cold, sadistic edge. He takes visible pleasure in combat, often toying with his opponents rather than dispatching them quickly, demonstrating a cruel and arrogant demeanor that contrasts with the discipline he might have possessed in life. His motivations are tied to his rebirth: he is driven by the immense power granted by the demon realm and a lingering attachment to his former glory as a peerless swordsman, making him a willing instrument of chaos. Within the story, his role is that of a high-ranking enforcer among the resurrected army, serving under the command of Amakusa Shiro or Mori Soiken. He acts as a direct threat to the protagonist, Yagyu Jubei Mitsuyoshi, engaging him and his allies in fierce combat. His most notable confrontation occurs at the Kagiya crossroads in Iga-Ueno, a deliberate echo of his famous historical duel, where he faces Jubei in a climactic battle that tests the hero's resolve. Key relationships include his subordination to Mori Soiken and Amakusa Shiro, his fellowship with the other resurrected masters such as Miyamoto Musashi and Hozoin Inshun, and his adversarial connection with Yagyu Jubei, whom he respects as a worthy opponent. Araki Mataemon's development is minimal as an undead antagonist; he remains a static force of destruction and pride, though his eventual defeat forces him to acknowledge the limits of even the demon realm's power. His notable abilities include superhuman strength, speed, and endurance granted by his resurrection, as well as masterful swordsmanship rooted in the Yagyu Shinkage-ryu style. He wields a katana with devastating precision and is capable of cutting through obstacles with supernatural ease, often remarking on the augmented power of his body. His fighting style is aggressive and relentless, reflecting his sadistic nature, and he is depicted as nearly invincible until faced by a protagonist of equal or greater skill.