Emperor was friend with Galen, as he was a member of the elite Golden Demon squad together with him. When he was still a prince, Emperor owned a blade known as the legendary shadow sword. Shadow, who brought along the strongest Legionaries with him, came to the young Emperor in order to retrieve the sword. He refused and he single-handedly defeat the Legionaries. After witnessing this, Shadow concluded that this nation can help him destroying The Sphere. After Emperor's father agreed to help Shadow, they built the Sphere Temple to keep The Sphere. Later, he replaced his father as the ruler of Dynasty and became The Sphere keeper and The First Arrow.
Through the suggestion of Galen, The Second Arrow, Emperor then stopped trying to destroy The Sphere and instead started researching its power in the hope of helping his empire flourish. This angered Shadow very much to the point that he became the enemy of Dynasty, which in turn also made the Legion confused by such volatile disposition. Since then, the two factions fell out with each other.
Not only keeping it, Emperor sometimes used The Sphere, in an attempt to research its power. Bolo, The Third Arrow, helped him overcome the side effects by creating the Void room, which the Emperor used and he often spent times there releasing himself from the Sphere.
Later, he sent June, his daughter who acts as his agent, to find the one chosen by The Sphere.
The player and June go to the palace to talk with Emperor regarding Deng Rao's attack to the Legion and what has to be done to prevent the war. However, the Emperor, along with the Shadow Sphere, are missing and no one knows where he is.
His disappearance has caused a bigger trouble, as the Legion has sent their Ambassador to discuss Deng Rao's attack with the Emperor. Because he could not meet with the Emperor, the Legion thinks that the Dynasty really seeking to wage war and responds by sending their army to invade Dynasty capital.
According to Itu, there were a few people in Shadow form in the palace that night. He is outnumbered and knocked out, and the Emperor and Shadow Sphere are no more when he regained consciousness. Kibo was also there, and she was in account with Deng Rao and the Ambassador, which implies that they may know something or may even involved in a scheme.
The Emperor's fate still remained unclear. Bolo's claim that something has changed inside of him does not help making things clear either. June accuses Bolo for causing it, stating that he must have changed his mind somehow.
After the trio meet with Galen, he guides them to the Emperor, who is now quarantined at the village with the blasted rig. June is relieved to find her father is alive and well. Emperor then reveals that Kibo saved him from a monster. It was the monster that destroyed the rig. That was the last time the Emperor had the Sphere. It was currently staying at the Sphere Temple, the only place that can hold its forces. If the Sphere loses its keeper, Shadow Sphere will consume the whole world. The party then goes to the Void room. They go there to get to the Sphere Temple using an intensified simulation. However, Emperor suddenly get possessed by the monster and prevent the player from getting the Sphere. The player enters the Void room and fights the possessed Emperor. Due to the monster's possession, the Emperor gained a powerful Shadow form, which allows him to transform to a humanoid Shadow monster that is very agile. Despite this, the player is victorious against the Emperor. After being freed from the monster, the Emperor will returns to the capital soon after he recovered.
Emperor is fought as the third and last boss of Chapter III. He fights with the Dynasty fighting style, does not use any weapon, and utilizes two Shadow abilities and a unique Shadow form. The fight consists of up to five rounds, and the player must score three victories in order to win.
The Emperor gained a different Shadow form than other opponents. Instead of being covered in Shadow energy with glowing eyes, Emperor will transform into an agile humanoid Shadow monster with big, sharp claws on his hands, which he uses as primary offense. After transforming, the Shadow monster form will not wear off and the Emperor will stay in Shadow monster form for the rest of the fight.
Emperor is also a playable character in Chapter VI. The players will fight as a younger Emperor during the flashback in Shadow Mind's story. He is equipped with Dragon's Roar and Northern Lights. Young Emperor does not have any perks or special moves on his equipment, but he can uses the same perks and special moves as the ones equipped on the players' owned Dragon's Roar and/or Northern Lights.
- In Chapter I, June informs that anyone who touched The Sphere will be turned into a beast, a very similar case the Emperor experienced in Chapter III.
- In Chapter V, Itu concludes that the case of Moira with the Scourge disease resembles what happened to the Emperor. Which means that after the explosion, the monster is hiding inside the Emperor all the time until the party reached the Void Room.