Nizaemon Yamamura is a historical Japanese painter who lived around the 17th or 18th century and serves as the postmortem primary antagonist in the story Rohan at the Louvre. He is best known for discovering the darkest pigment in the world, which he obtained by cutting down an ancient, protected tree. This act led to his execution for violating the law. His only surviving work is a painting titled Under the Moon, which depicts a portrait of his wife, Nanase Kishibe. Nanase is one of Rohan Kishibe’s ancestors, making Nizaemon a distant relative of the protagonist. After Nizaemon’s execution, Nanase died of illness shortly afterward, and the painting is said to carry a curse imbued with hatred, influenced by the circumstances of their deaths.

Nizaemon’s background as an artist is defined by his intense dedication to his craft. His discovery of the unique black pigment reflects a deep commitment to artistic perfection, but also a disregard for the consequences, which ultimately cost him his life. His motivation appears to be twofold: the pursuit of an unparalleled artistic medium and a personal desire to capture the likeness of his wife in the purest, darkest color. This combination of ambition and love gives the resulting painting an emotional weight that transcends its physical form.

In the story, Nizaemon’s role is that of the originating force behind the curse that drives the plot. He does not appear alive, but his presence is felt through the supernatural effects of his painting, which is stored in the basement archives of the Louvre. The painting, Under the Moon, becomes a malevolent entity that kills anyone who gazes upon it for too long, using illusions and creatures to trap and destroy investigators. Rohan Kishibe, drawn by the legend of the blackest painting, travels to the Louvre to uncover the truth, and he and his companions are confronted by this danger. Nizaemon’s relationship with Nanase is central: his love for her is immortalized in the painting, but his bitterness and resentment over his execution and her death transformed the artwork into a vessel of malice.

Nizaemon’s own personality is not directly depicted in the story, but the curse suggests he was a man of strong emotions—love, pride, and anger—that survived his death. His development as a character is entirely posthumous; the narrative traces the aftermath of his actions and the legacy of his art. He has no supernatural abilities himself, but his painting exhibits the power to kill, manipulate perceptions, and trap victims in a nightmarish space. This ability is a direct result of the pigment he created and the curse that was born from his and his wife’s tragic fates.