The Emperor was the former monarch of The Empire, and a minor antagonist of the Akame ga Kill series. He was a naive young boy who wished to lead his people to a bright future. Unfortunately, due to the Prime Minister's influence, he was immensely ignorant to the suffering of his people and through this negligence contributed to the decay and collapse of the Empire.
The Emperor was a young boy with green shoulder-length hair which was braided on the sides and green eyes. He wore a purple outfit with white boots and a blue mantle, as well as a large headdress. He also carried a golden scepter with a blue orb attached to it.
Being only a child, the Emperor was immensely naive and blindly trusting in the Prime Minister, who used him as a puppet to do whatever he wanted. Constantly under the watchful gaze of his "most trusted adviser", the Emperor's perception of morality became warped as he was incapable of discerning right from wrong, believing that all he does is for the good of the Empire. He obediently listened to Honest without question and asked for his approval in the decisions he had made, as shown when he sentenced a man to death using a particularly horrific execution method for being against some of the decided political measures he had taken.
Outside of his duties, however, he was shown to be a kind and cheerful person who only wanted to help others to the best of his abilities, as shown when he wanted to help Esdeath find a lover. He was also curious, as he asked Honest why she wants to find a lover, to which Honest happily explained.
After releasing and bonding with the Imperial Family's personal Teigu, Shikoutazer. The Emperor's personality was shown to have been changed drastically, becoming much more vicious, arrogant and short tempered. Furthermore, his delusionalism was also shown to have increased dramatically, as seen where he had little to no hesitation to unleashing the incredibly powerful and destructive attacks of his Teigu inside his own capital that while indeed succeeding to kill a large chunk of the revolutionary army, the collateral damage also killed numerous imperial soldiers and even civilians from the capital. Later after seeing his soldiers abandoning the battle against the revolutionary army and instead prioritized evacuating the capital due to the onslaught of his own attacks and ignoring the safety of his own loyal citizens, the Emperor fell into hysterical denial of his own actions and proclaimed them all to be traitors despite understanding his actions.
Following the defeat of the Empire, the young ruler came to realize the error of his ways. With Honest's manipulations laid bare he finally realized how far he had strayed from the path he'd intended. Even when faced with his own execution, rather than despair, the Emperor showed a strong resolve to see the end of his rule with a brave face and calmly accepted his fate.
As seen in his final moments, despite everything that happened, the Emperor was shown to still deeply care for his country. With his final request to Najenda was to rebuild it and undo all the wrong he and the Prime Minister had done to their nation.
Some time ago before the series' start, the Emperor won a battle of succession to the throne of the Empire thanks to Honest's shrewd tactics. He has been used by him as a puppet ruler ever since. His parents were murdered by Honest so the Minister has tighter control over the young boy who did not know the truth.
Due to his young age, naivety and innocence, the Emperor innocently believed whatever the Prime Minister told him, no matter how horrific his decrees and orders were. This eventually caused an adverse development in the young boy's mind, causing him to develop the belief that his actions, no matter how monstrous, was for the better of his country.
After the Revolutionary Army triumphed in its war against the empire, the Emperor was arrested and publicly beheaded for his crimes, following the Minister's own execution. Unlike the former, however, the Emperor stayed firm and resolute during his execution, accepting that he had brought this fate upon himself by not being the strong leader he wanted to be.