Koumei is also known as Zhuge Liang in the original Romance of the Three Kingdoms. His route is the best in this game. No wonder he won the character poll.
Koumei a wise strategists also known as “The Sleeping Dragon”. He was the one who gave directions to Hana when she first came to that world. Gentoku wanted him to join his army, yet he made Hana his apprentice and sent her instead. He kept coming and disappearing in front of Hana instead of joining Gentoku’s army because “it’s not the time yet”.
After the Battle of Red Cliffs, Hana was thinking about she doesn’t want to fight when suddenly the book glowed. Hana got thrown back in time alone to the Yellow Turban Rebellion era.
In the mountains she met a boy in the mountains named Ryou, who was running away from some bandits. His father was the governor’s deputy in Mt. Tai and fought the bandits alone so that Ryou could escape. Ryou’s foot was wounded, so Hana helped him in cleaning and treating his wound and carried him back home.
From the servant in Ryou’s mansion, Hana learned more about the situation at the time. With only the “way of supreme peace” (太平道 / Taiheidou) as her keyword, Hana travelled alone trying to find a plan to avoid fighting. On the way she met two followers (which means that they were rebellion members) and was taken to meet the leader. To ensure they will accept her plan, Hana faked her identity and said she was sent by a Nanka Rousen (Immortal of the Southern Land) to deliver a prophecy.
To prove that her prophecy and the strategies are real, the leader asked her to take Houkou first. Unbelievable as it was, she did manage take it only with two soldiers: Anji and Kishou.
Before leaving to take Rakuyou, Hana visited Ryou’s mansion to say goodbye. However, the servant shooed her out thinking she was a member of the rebellion. Ryou then came out and asked if she was their enemy. Hana answered that she didn’t know her position, but she hates the world where Ryou’s father might get killed. She saw hurt in his eyes, but she couldn’t say anything more and went back to the rebellion camp.
Not too long after that, people found Ryou sneaking into the camp. He ruined their food supply by using wolves and got caught, but Hana helped him by saying that he’s her apprentice. When she asked for explanation later, Ryou answered that he came to get revenge, but he was surprised when he saw there were also women and children in the rebellion.
Seeing Ryou losing direction, Hana told him Koumei’s words to keep learning and deepen his knowledge since it will eventually becomes his power. Ever since that day Ryou looked up to Hana as his teacher.
Despite Hana telling him to go home, he tagged along because he wanted to see what was happening in his country. Ryou was also the one who suggested the idea of everyone wearing yellow scarves and establishing rules to symbolize unity, giving the rebellion a bigger chance to succeed.
After hearing Anji’s plan to marry Hana after all the fighting ends, Ryou asked Hana if she has a person she wants to marry. Hana answered that she has a person she depend upon and respect: her teacher, Koumei. Ryou also asked Hana to stay after the rebellion succeed, but Hana said she must go back because there were people she needs to help. Ryou fell silent and Hana apologized.
What Hana didn’t know is, Ryou deliberately didn’t tell her that Anji was waiting for her at night. That night Anji proposed to Hana. He stood outside of her tent, not knowing that the person he was talking to was actually Ryou.
The rebellion eventually succeeded in taking Rakuyou. Right after the fight ended, the book glowed and Hana was taken back to the original time. Just before she disappeared Ryou asked her to take him, but she refused. He then told her to erase all the fighting, and that he will walk along the same path.
Koumei was in her room when Hana got back. They then discussed about their next plan. He told her that they will be busy since she has to fulfill her promise to Ryou, to erase all the fight from the lands. Hana was surprised that Koumei knew about that, and he showed her a scar in his leg which proved that Ryou was actually Koumei when he was small. Koumei then informed that he started working for Gentoku as well.
One day during a break between work, Koumei rested his head on Hana’s lap. Seeing him sleeping, Hana also fell asleep for a moment. Koumei told her to have some wariness in her, since “a man will try to attack whenever he gets the chance”. Hana asked him if he has someone he loves, and he answered that he does.. but that person wasn’t there. He then told her that she was his first love and fell asleep again while Hana thought about the person he loves.
After taking Kouyou and conquered Southern Keishuu, Koumei suggested that they persuade Moutoku’s Seishuuhei — soldiers who already fought ever since his power was still small. Hana doubted it’d work but eventually found out that Seishuuhei was the Yellow Turban rebellion members whom she helped in the past including Anji and Kishou.
They were really thankful to her for helping them in the past, and said that their loyalty actually lies in her. With their help, Gentoku’s army was able to take Jouyou successfully.
Hana met Koumei’s friend who visited their office some days later. From him, Hana found out about Koumei keeps rejecting marriage ideas suggested by people around him because he was still thinking about someone who wasn’t there. Hana took it as Koumei still loving someone who was already dead.
When Koumei kissed her forehead to wish her good luck in fulfilling her promise to him, Hana asked her if he didn’t think of anything while doing that. He answered it’s only for good luck and not a big deal. Hana then asked if the reason he didn’t want to get married is because he still loves that certain person. Koumei confirmed that it’s true, and that it’s got nothing to do with her. Hana felt pain in her heart, thinking that Koumei only saw her as his apprentice and nothing more.
Some days later, Koumei’s acquaintance suggested him to get married. He already introduced him to his daughter before, but he refused. This time, he tried to introduce him to his acquaintance’s daughter. In order to make him give up, Koumei pretended to be lovers with Hana in the garden. She couldn’t bear being treated like that when he doesn’t feel anything towards her, so she ran away feeling sad right after the act was over.
Thinking that Koumei only thought of her as his apprentice, Hana decided to go home after they took Ekishuu, securing Gentoku’s position and fulfilling her promise to Ryou to put an end to all the fighting.
After successfully taking Ekishuu, Hana gazed at Koumei who was standing next to Gentoku, announcing their authority and desire to work towards the same goal. She thought about going home since it’d be fine without her here, and Fuyou noticed she gazed at Koumei with sad eyes.
Days passed with Hana helping Koumei with various tasks and didn’t have the chance to tell him about her going home. Even so, she enjoyed being with him. By his suggestion, Hana also left the book in her room to avoid accidental departures.
One day, Koumei went to town with Hana. They were supposed to go on a patrol, monitoring prices and conditions, but it feels more like a date since he held her hand. Hana noticed how he was always looking at a lot of things and asked if there’s something she could do to help, but Koumei only answered that Hana’s skill was limited. She thought about how she wants to support him in everything he does.
When they went back to the castle on evening, Koumei asked if Hana has found a path to go home. He then took out the book that Hana supposedly left in her room. It turns out that Koumei already knew about the book, and said that the book’s power and Hana herself wasn’t needed anymore since people will build their own country.
Hana asked if that means Koumei doesn’t need her anymore, and he said yes. He then flipped the book until the last page and light enveloped her, ready to take her home despite her protests. As she started to disappear Hana wished that she could stay with him.
Hana found herself back in the book’s world. She wasn’t taken back home, and the book disappeared by itself. Koumei was sitting alone on the ground, looking both sad and surprised that Hana didn’t disappear. She said that she will study a lot of things so that she would be useful without the book. Because she wants to stay by his side.
Koumei hugged her and said after all the things she said, he won’t ever return her to her own world. He searched for her after she disappeared in Rakuyou ten years ago, believing that they will meet once again even though she was nowhere to be found then.
When they did meet again, he knew that Hana eventually will return to her own world, so he told himself that his first love was no longer in this world. The person he loves has always been her all along, and all that he wished for was for her to be happy. After Hana said that she loves him as well, Koumei gave up trying to cover his feelings. He couldn’t deceive his own feelings anymore, because he loves her that much.
In the epilogue Hana tried to call him Koumei-san instead of the usual ‘Shishou’ (teacher). He was both happy and embarrassed when she called his name in front of the others. To get his revenge, he told her to always call him by his name whenever they were alone.