Kohei Nishimura, once the formidable Shogun of Japan, now a bitter shadow of his former self, is consumed by a desire to bring about the nation's downfall. At sixty-two, his once proud stature is bent, his gray hair tied back in a severe bun, and his face etched with the deep lines of rage and sorrow. He wears the traditional robes of a high-ranking samurai, but they hang loosely on his frame, a testament to the weight he has lost to his obsession. Kohei's eyes, sharp and calculating, are the only feature that still hints at the brilliant strategist he once was.

In his youth, Kohei was indeed friends with the fathers of Kikeya and Kagome Hikari, and together they orchestrated a covert conspiracy aimed at manipulating the Hikari family's lineage for their own gain. This plot, however, backfired, leading to the mysterious maps being scarred into Kikeya and Kagome's backs. These maps, known only to Kohei and a select few, lead to a hidden cache of ancient relics that could either save or doom Japan, depending on who controls them.

Kohei's life is plagued by conflicts: his strained relationship with his daughter Naoko, who is smitten with Kikeya Hikari, and the existence of his secret second daughter, Kotomi, whose very life is a testament to his past indiscretions. Kohei's intelligence is his greatest weapon; he uses it to manipulate those around him, weaving a web of deceit that he hopes will lead to Japan's destruction. Yet, his plans are constantly thwarted by the resilience of the Hikari siblings and the unexpected loyalty of some of his former allies.

Despite his villainy, Kohei's unique trait is his penchant for calligraphy, a skill he uses to encode his plans in scrolls that only he can decipher. This, combined with his twisted worldview, makes him a formidable and intriguing antagonist, whose end will likely be as dramatic as the life he has led.