Saburo was right (Situational Irony)
At the beginning of the film, Saburo appears to be the most irreverent and disrespectful of Ichimonji's sons, yet he warns that his brothers are simply being flattering in order to win their father's favor. A grave irony occurs when Saburo's instincts about his brothers' characters are proven correct, and Ichimonji is disrespected by both Taro and Jiro. It turns out that Saburo was in fact that only son that actually cared about his father's well-being, even though his father mistook this loyalty for disrespect and banished him from the kingdom.
The Blind Peasant (Situational Irony)
After Ichimonji escapes from near-death at the Third Castle, he goes mad with visions of his past sins as a warlord. Tango and Kyoami take him to a peasant's hut in the countryside to help him heal. Ironically enough, the peasant is the brother of Jiro's wife, Sué, whose family was attacked by Ichimonji many years ago. Ichimonji is responsible for the sorry fate of the man on whom he must now rely for shelter, an ironic twist.
Better off Mad (Situational Irony)
When Ichimonji goes mad, he finally begins to develop a conscience and see the ways that his war-mongering has hurt people in his past. He feels immense guilt for his misdeeds, but he is also completely insane. Ironically enough, it is only when he is mad that he is able to have some kind of ethical compass. When he "recovers" from his madness in the blind peasant's hut, Kyoami jokes that he was "better off mad." In the film, madness is a saner moral position than sanity.
Kaede's proposal (Dramatic Irony)
After Jiro defeats Taro, Kaede visits him in the court, alone. She acts as though she is going to be supplicant, before pulling out a knife and threatening to kill him for the sins he has committed. She then makes him a proposal: she will remain silent about all of his misdeeds if he keeps her in power and looks after her. This moment of blackmail is an instance of dramatic irony, in which we know more than the other characters about Kaede's actions.
