The character known simply as Emperor is the ruling monarch of the Empire in the series. He is a young boy who ascended to the throne at a very early age, making him a child ruler entirely dependent on the guidance of others to manage the affairs of the state. His background is marked by political machination, as it was through the shrewd and ruthless tactics of his most trusted advisor, Prime Minister Honest, that he won the battle of succession to the throne after his parents were killed. Unaware of the truth behind his rise to power, the Emperor governs from the Imperial Capital, believing himself to be a righteous leader.

In terms of personality, the Emperor is defined by his profound naivety and gullibility. He possesses an innocent and well-meaning core, genuinely wishing to lead his people toward a great and prosperous future. However, because of his youth and inexperience, he is incredibly easy to influence. He places his complete and unwavering trust in Prime Minister Honest, viewing him as a benevolent and essential advisor rather than the corrupt and manipulative figure he truly is. Consequently, the Emperor obediently listens to Honest without question and prioritizes his opinions in all political decisions, incapable of discerning right from wrong or recognizing the immense suffering his decrees inflict upon the citizenry. While he is not depicted as a complete puppet without his own will, his perception of morality is so warped by Honest that he believes all of his actions, no matter how horrific, are ultimately for the good of the Empire.

The Emperor’s primary motivation is the preservation of his nation and his position as its ruler. As the Revolutionary Army closes in on the capital, he becomes deeply concerned for the future of his home, feeling that the nation is on the brink of collapse. Acting on the instigation of Prime Minister Honest, he resolves to use the ultimate weapon at his disposal to crush the rebellion and protect his legacy. His role in the story is that of a tragic antagonist. He is the figurehead of a corrupt regime, and his final stand serves as the last obstacle for the Revolutionary Army to overcome. The final battle against him is the climax of the siege on the Imperial Capital, where he serves as a direct opponent for the protagonist Tatsumi.

The Emperor's most significant relationship is with Prime Minister Honest, who acts as his puppet master. The Emperor’s absolute faith in Honest allows the minister to completely manipulate him, turning the child into a pawn for his own decadent and cruel schemes. This relationship is the central tragedy of the character, as he is corrupted not by his own malice but by the influence of a trusted figure. His key oppositional relationship is with Tatsumi and the Night Raid, who fight to liberate the Empire from his rule. During the final battle, he serves as the main opponent for Tatsumi, who tries in vain to reason with him as they fight. He also receives unexpected aid from Wave, a former enemy, who fights alongside Tatsumi to stop the Emperor’s rampage, showcasing how the Emperor’s blind actions have alienated even his own former allies.

The character undergoes a tragic and dramatic development in his final moments. Initially, after being convinced by Honest, he pilots the ultimate Teigu, Shikoutazer, with the intention of protecting the Empire. However, as Tatsumi begins to gain the upper hand in their battle, Honest activates the Teigu’s hidden trump card, the Purge Mode. This mode brainwashes the Emperor, corrupting his mind and turning him into a ruthless tyrant consumed by bloodlust. In this berserker state, he indiscriminately slaughters everyone in his path, including his own soldiers and innocent citizens, which leads to the de facto collapse of the imperial forces. After his defeat, the Emperor is captured and imprisoned, where he is finally forced to confront the immense suffering he has caused. He shows deep remorse for his actions and, in a final act of atonement, faces his execution by guillotine with a resolute and dignified attitude, accepting his fate as his final duty.

Regarding abilities, the Emperor himself is a defenseless child and possesses no personal combat skills. His power comes entirely from his authority over the ultimate Teigu, Shikoutazer, also known as Primus Imperator. This colossal suit of armor is said to be the first and most powerful of the 48 Teigu, belonging exclusively to the royal family. The armor possesses overwhelming destructive power, capable of firing energy beams that can level entire buildings and wipe out armies. Its most dangerous feature is Purge Mode, a hidden trump card that corrupts the user’s mind, turning them into an uncontrollable berserker who attacks friend and foe alike. Despite its immense power, the Shikoutazer has a critical weakness in its chest, which can be exploited to destroy it.