Nizaemon Yamamura (山村 仁左右衛門, Yamamura Nizaemon) is a tertiary character featured in the one-shot Rohan au Louvre.
In the manga, little is known of Nizaemon when he was alive, but he becomes full of hatred upon his execution.
The live-action film expands on his personality. He was a skilled and passionate artist who loved to experiment with his paintings. Despite his prestigious background, Nizaemon was a humble and genuine individual, never shying away from honest criticism and valuing sincerity. His love for his wife Nanase blossomed quickly; he often painted her, especially paying meticulous attention to the details of her captivating black hair. Despite disapproval and subsequent disownment from his family, Nizaemon remained steadfast in his pursuit of artistic expression and continued to paint in different styles.
Collecting the black sap from the sacred tree triggered an eerie transformation in his personality, almost as if he were possessed. Unbeknownst to him, the black sap concealed the essence of a small black spider that had dwelled within the darkness of the sacred tree for thousands of years, drawing forth darker emotions within him. For instance, when his wife is harmed by magistrate officers, he goes as far as to murder them with an axe.
Around 310 years prior to the events in Rohan au Louvre, Nizaemon married Nanase Kishibe. He had discovered a pigment of a unknown blackness in the trunk of a sacred tree and extracted it to use in his work "Under the Moon", a painting that featured Nanase. However, chopping down the tree was forbidden by decree, and so Nizaemon was executed just after his wedding with Nanase.
According to legend, Nizaemon had drawn the most evil and black painting in the world. Due to the hatred he held while he was executed, that hate was transferred to the painting, giving it life and a murderous intent. In 1989, it was acquired by the Louvre museum and kept in the Z-13 warehouse, which later was abandoned. The painting was the only one not moved to a safer place, implied to be because anyone who approached it would be killed due to its curse.
Rohan Kishibe, Gaucher, Noguchi, and two firefighters go to Z-13 at the Louvre to investigate Nizaemon's painting. Aside from Rohan, everyone is killed by its illusions before Rohan erases his own memories. After escaping, Rohan tries to find out what happened to the painting. He learns that it was incinerated after a thorough analysis by scientists but hasn't been able to confirm whether that is the truth.
Nizaemon was the eldest son of the Yamamura family, which served as official painters for generations. One day in August, Nizaemon had an arranged marriage with Nanase Kishibe. The two loved each other and Nizaemon would frequently paint her, particularly detailing her hair. Nizaemon had once asked Nanase her thoughts on one of his paintings and she honestly replied that she didn't think it was good. He appreciated her honesty, stating that it was an imitation of a Dutch painting he saw while studying in Edo. Nizaemon did not only paint traditional styles but also in the ukiyo-e style which was popular with townspeople. His father scolded him for this, as it was unacceptable for him to paint things for commoners given their social status. Since Nizaemon disagreed with his father, he was disowned from the family. The chief priest of their local temple allowed him and Nanase to move to a hermitage in the corner in the temple, where Nizaemon continued to paint. Although he lost his status as an official painter, Nizaemon made a living by selling fusuma (sliding door) and byobu (folding screen) paintings to merchants. Meanwhile, Nanase would take care of the household chores.
At some point, Nizaemon was bothered that he didn't have black ink that was dark enough to properly depict Nanase's black hair. At the same time, Nanase suddenly fell gravely ill, no longer having energy in her hands or feet. Nizaemon was not making enough money to support themselves, as his savings went toward paying for doctors and medications. Thus, he swallowed his pride and asked his father to accept him back into the family. His father agreed, but only if Nizaemon would show him a painting that surpasses his own. The doctors and medicine did not help Nanase, so her only hope was to pray to the gods. While praying, she came across black sap flowing from the sacred tree in the temple. Feeling as if that was a sign from her prayers, she collected the sap and gave it to Nizaemon to use for his painting. She didn't want to tell him where the sap came from, but continued collecting it for him. However, Nizaemon followed her one day and found where she was getting it from. From then on, Nizaemon started collecting the sap from the tree himself.
Others found out about Nizaemon collecting the sap, such as his younger brother, Samanosuke Yamamura. Samanosuke filed a complaint with the magistrate's office, since he intended to take over the Yamamura household instead of his brother. The officials then arrested Nizaemon as it was a taboo to harm the sacred tree. Nizaemon claimed he did not harm it and only collected its sap, but the officials said he should not even touch it. Feeling guilty, Nanase confessed that she was the one who did it rather than her husband. She grabbed onto the leg of one of the officials to prevent them from harming Nizaemon, but they struck her with a stick. Nizaemon shook off the officials grabbing him and rushed to Nanase's side. As Nanase's vision started to blur, she witnessed him grabbing an axe and killing the officials. He then struck down the sacred tree with the axe, as the sap in his hands mixed with the blood of the officials.
Sitting by Nanase's side, Nizaemon started to paint with the black ink. Nanase realized that its true nature was a small black spider, which had been inside the darkness of the sacred tree for perhaps thousands of years. Nizaemon finished the painting extremely quickly with a speed that exceeded human capabilities. However, his life also burned out when he completed it. He and his wife died together as their sorrows, anger, regrets, and Nizaemon's resentment seeped into the painting.
Hundreds of years later, Nanase's ghost appears before her descendant, Rohan Kishibe. The two become close and Nanase tells him how he resembles Nizaemon. Nanase then disappears so that Rohan does not become like Nizaemon.
Rohan Kishibe, Kyoka Izumi, Emma Noguchi, Ryunosuke Tatsumi, Nicolas Thomas, and Hugo Renard go to Z-13 at the Louvre to investigate Nizaemon's painting. Besides Kyoka, all of them are affected by the curse of Nizaemon's painting. Rohan's "regret" manifested as Nizaemon, who resembled a samurai but wielded an axe. Nizaemon swings his axe at Rohan. Although Rohan feels as if his flesh got torn apart, it was only an illusion, and black sprayed out of him rather than blood. Not understanding the relationship between him and Nizaemon, Rohan attempts to use Heaven's Door to read his memories, but Nizaemon's pages were completely black. Since Nizaemon wasn't actually a soul but rather a dead person living within the memories of someone else, he had no memories or humanity himself for Heaven's Door to read.
Fire spreads throughout the warehouse, with heat roasting Rohan's skin. As Rohan is cornered by the flames and by Nizaemon who was about to strike with his axe again, Nanase appears behind Nizaemon and holds him down. Rohan ultimately escapes from the curse by using Heaven's Door to temporarily make him forget everything. After escaping, he assumes the fire burned down the painting. Rohan later visits Nanase and Nizaemon's gravestones. Nanase's ghost appears in front of him one last time. She apologizes to Rohan for getting him involved, but she and Nizaemon are now freed from their regrets.