In the 2007 film Sukiyaki Western Django, the character known as Boss is Kiyomori, the leader of the red-clad Heike clan. His full name, as spoken by characters within the story, is often given as Boss Kiyomori, though he also insists on being called Henry, a reference that reflects the film's blending of Japanese history with Western influences, specifically the English Wars of the Roses and the plays of Shakespeare. Kiyomori is a violent and imposing figure, yet his personality is defined by a deep-seated cowardice that contradicts his position as a ruthless gang leader. He is described as being bestial and loud, preferring to use his own men as human shields rather than face danger directly.

The primary motivation for Boss Kiyomori and his Heike clan is the pursuit of a legendary treasure, a cache of gold rumored to be hidden in the desolate town where the film takes place. His background is tied to the ancient Genpei War, as the Heike are presented as descendants of the historical Taira clan, locked in a centuries-old rivalry with the Genji, who wear white. Kiyomori's goal is not merely to find the gold but to dominate his enemies completely, and he pursues this objective with a complete disregard for human life, whether it belongs to his foes or his own followers.

In the story, Kiyomori serves as the primary antagonist and the violent catalyst for much of the town's suffering. His role is established early on when he murders the town's mayor upon arriving to search for gold, quickly taking over the area and establishing his brutal rule. This act sets the stage for the arrival of the rival Genji clan and the ensuing conflict that terrorizes the remaining inhabitants. One of his most defining and heinous actions is the murder of Akira, a member of his own clan who had married a Genji woman, Shizuka. After killing Akira in cold blood, Kiyomori then rapes Shizuka, an act of cruelty that leaves her son, Heihachi, mute from trauma and sets Shizuka on a path of survival as a prostitute under the protection of the Genji.

Key relationships are defined by rivalry and exploitation. His primary opposition is the Genji leader, Yoshitsune, a charismatic and flamboyant swordsman who provides a direct contrast to Kiyomori's brutish and cowardly nature. While Yoshitsune seeks challenge and glory, Kiyomori seeks victory at any cost, often through treachery. He also has a relationship with the town's sheriff, whom he uses as a pawn and a shield. His cruelty directly creates an enemy in Ruriko, an elderly bar owner who is secretly the legendary gunslinger Bloody Benten and the mother of Akira. Kiyomori's murder of her son fuels her thirst for revenge, which becomes a central driving force of the film's final act.

Boss Kiyomori shows little to no development or redeeming arc throughout the narrative; he remains a consistently vile and self-serving tyrant. His most notable ability is his tactical cunning in acquiring new weapons, such as when he successfully ambushes a Genji wagon to steal a powerful Gatling gun hidden inside a coffin. However, his most defining characteristic is his cowardice. In combat, he frequently cowers behind his subordinates and the sheriff, making comments about needing to fatten them up as better protection. This combination of cruelty and cowardice ultimately leads to his downfall. After a violent confrontation, he is confronted and killed by Ruriko, who finally avenges her son's death, putting an end to his reign of terror in the town.