Ryosai wears a simple headgear and robe with a red sash crossing his chest. He has neck length black hair and a small beard that curls and splits in the middle and dark circles around his eyes. His sword is always at his side.
Ryosai is openly hostile towards the Kouga tribe and was not above insulting the people and calling them uncivilized or mongrels. He has great pride in the Kou Empire and tells the Kouga tribe that they should be happy they were "saving" them from the life of scum. He does not agree with Hakuei's ideals and manipulates others to have her give command to army they have in order to create war. He holds great pride towards himself and is angered when Hakuei belittles him and claimed because of her, he couldn't become a general for the army she was leading.
He appears alongside Hakuei when the princess went to make peaceful negotiations with the Kouga tribe to unite with the Kou Empire.
As Hakuei makes a diplomatic visit to the nomadic Kouga clan, she states that they should unite with the Kou Empire in order to "unite the world"; Ryosai asks her if: "Such uncivilized people understand... such majestic ideals?" before being subsequently hushed by the princess. When Baba asks the princess for time so the clan could think on her offer Ryosai looks disgruntled at their answer. As Toya offers Hakuei a drink with horse's milk Ryosai rudely slaps the drink onto Toya before the princess could accept it. Hakuei angrily asks him what he was doing and he calmly replies that he was only doing his duty; he stated he couldn't let an honorable princess like Hakuei drink a foreign liquid from a foreigner and that a horse's milk is the drink of a mongrel. Hakuei once more silences Ryosai, glaring at him. Ryosai tells her that she needs to be more straightforward and then proceeds to vehemently tells the Kouga tribe that they would be under the Kou Empire's control adding that the tribe should be thankful that the Kou Empire came to save them, because their way of life was so lowly. His last threat was that if they wanted to live the happy life of a normal person, then they should surrender.
Ryosai is soon surprised when he is attacked from behind by Dorji, splitting the back of his clothing and leaving a cut on his back. The Kouga tribe angrily rallies with Dorji telling him they would not surrender themselves to the Kou Empire while throwing rocks at the man. Hakuei and Seisyun Ri quickly pull Dorji back telling him they needed to leave.
Back at camp, Ryosai is bandaged from Droji's attack and tells the princess that they were ready for a full assault on her orders. Hakuei rejects the idea and says they need to be calm about this, after she leaves he loudly states that Hakuei was too naive and if she didn't understand the art of war. A soldier nearby angrily condones him for speaking lowly about the princess.
One night a general returns wounded, telling Hakuei that he was attacked from a Kouga clan member and Ryosai angrily tells Hakuei that the Kouga clan was barbaric and negotiations were useless. He suggests that they should just destroy them now instead of talking Hakuei rejects his ideas again and hurriedly leaves to go sort out this matter. Ryosai looks at Hakuei and tells her that she can't make these decisions on her own; since she is the former king's daughter, she can only obtain the title general because it was a gift from the current king. He apologized for not agreeing with her, the generals actions, but said he was on orders to watch over her. Hakuei stubbornly says she will speak with the Kouga clan peacefully and leaves Ryosai temporarily in charge of the army while she was gone. He thanks her and bows, hiding a dark grin.
The general who lead the slave hunt tells Ryosai what would he do now that he was in command since if Hakuei returned it would lead to their previous slave hunting. Ryosai admitted that was a problem and that he worried for the princess if she would make alive while polishing his sword. He lays his head against it, describing a scene where the angry tribe who suffered slave hunting, and the shooting of their elder, would have killed the princess off already. The soldiers become horrified at what could happen to Hakuei and ask why Ryosai was doing this and he simply stated that he liked it: war. He claimed to hate "the idiots who say they hate war" and becoming outrageous and killing each other whilst revealing their true identity, would ultimately create war.
Upon Hakuei's return from her negotiations with the Kouga clan, Ryosai greets her with an army declaring war. Once Hakuei has informed Ryosai that the Kouga are now one with the empire, he smirks at how slave hunting and the killing of their elder was enough for negotiations. Outraged, Hakuei yells at Ryosai that it was him all along and he admitted that was his plan and his future one was: the princess went to the Kouga tribe and was killed, Ryosai who was left went to kill the clan in revenge. Hakuei clamly mocks him, asking if a Senincho like him could order an entire army, and he angrily tells her that he wanted to be a the general of this army. He said that he would have been promoted to the leader of this army if only Hakuei hadn't come. But now that he had command of the army because she left, he prepared his men to fire. Hakuei mocks Ryosai one last time, telling him, "Traitor Ryosai, may the one who hurts their own name repent through death," Ryousai snaps and gives the signal for his archers to fire on the princess. However, the arrows fired would not touch Hakuei due to her "mysterious powers" as a "Dungeon Conquer" and orders a relentless attack upon Hakuei, adding that he will reward those who harm her with honor. He becomes outwardly terrified when Hakuei summons the powers of Paimon as she prepares to face off with him. A large tornado attacks the soldiers, Ryosai calmly says it's just wind and a Dungeon Conquer had a fatal weak point. As Hakuei and Seisyun's magoi depletes Hakuei orders Seisyun to capture Ryosai since they had shrunken his army. Seisyun rides towards Ryosai in order to take him out, but he calls upon Hakuei's entire army saying that "it comes to this" because Hakuei couldn't ambush.
Ryosai's army subdues Hakuei and Seisyun and as Ryosai kicks Hakuei calling her useless, he tells her not to worry and he would take care of her precious little brother Hakuryuu Ren by killing him. Hakuei goes into a rage and attacks Ryosai with a soldier's sword. Ryosai blocks her strike and says that they will settle on who the general will be when the soldiers shoot Hakuei with arrows. He laughs at her naivete and tells her she would be tortured to death. As he raises his sword while soldiers hold her down, he asks her what kind of imperial princess she was and that she was nothing but a small, small existence. He claimed that he would smash her in one hit like a piece of trash and is suddenly hit by Ugo, halting Ryosai's conspiracy towards Hakuei.
Later, Ryosai and his troops were captured and it could be hinted that Ryosai was executed for treason.
Ryosai is trained in swordplay.
Although Ryosai served under Hakuei, he thought her way of diplomacy was too weak and she needed to be more "straightforward". He does not agree with her way of thinking and once he is in command of her army, he shows his hatred for her and how he wanted to be a general instead of her. She mocked him after his betrayal and sentenced him to death.
- Ryosai's rank is a Senincho, which means he can only command up to 100 people.