Tsuchiya Kuon

About
Kuon (renameable) is the leader of the Tsuchiya zaibatsu. The organization which has grown tremendously rich and powerful in the 7 years since he began. This is most likely due to capital left by Tsuchiya Wakako's death which he decided to re-use like he has been taught.

His parents died when he was a child. This made him an orphan and left him to take care of his sickly sister, Tsuchiya Sera. Wakako saw great potential in him and adopted him, Kuon decided to cooperate to help Sera. Together with Toudou Sei and Tsuchiya Yuki, he managed to endure all of Wakako's harsh training and odd whims. During all of this he decided to adopt her last name as well.

He was 20 years old when Wakako died. He used her leftover capital to start his own businesses with Toudou Sei and Tsuchiya Yuki just like they've been taught. 7 years later their conglomerate is seemingly one of the most powerful in the entirety of Japan and a powerhouse worldwide.

Just before the start of Mugen Houyou, he is diagnosed with an unknown and uncurable illness. He is told he will die relatively soon, though they do not know when exactly. Treatments can prolong his life somewhat, but not endlessly. He feels this is not how he wants to live and he instead has his office floor transformed into a taishō style mansion. He also tells everyone in the mansion to wear period accurate clothes which everyone does with the exception of Sei and Tsuchiya Yuki. He surrounds himself with things and people he fancies and decides to live his final days in a debaucherous manner.

He is a pragmatic and decadent man. He always was something of a nihilist, but the education provided by Wakako only worsened this. At the start of the game, all he cares for is his enjoyment and to make sure that Tsuchiya Sera lives in comfort. His favourite activity was sex and it was probably the thing he engaged in the most. The first signs of his illness showed up during one of his many orgies. He is told to ease up on this for his heart, but he has no real interest in doing so/ He is currently married to Tsuchiya Yuki, but only for business reasons as foreigners are more likely to do business with him then.

The game has many endings, most showing Kuon softening up somewhat.

His relationship with Tsuchiya Sera during the game is that of a brother spoiling his sister far too much. She attempts to kill Yuki as she feels he hates her and so she hates her. If this is allowed Kuon is wracked with guilt, especially after they end up doing it together. He feels it is his fault she turned out the way she did and he decides to commit double suicide with her after their unofficial marriage. They tie each other together with a red string and jump off the building to meet their parents.

Toudou Sei is his servant before he is his brother. His main ending has Kuon collapse from overwork before dying as Sei is unwilling to ever go against or recommend anything that goes against what Kuon wishes to do. Kuon accepts that he will die and tells Sei he doesn't have to comfor him anymore. A joke ending has Kuon send him to the moon with a rocket they acquired, this collapses the business as the sickly Kuon and Yuki now have to handle the entire workload. Another joke ending has Kuon and Sei confess their love for each other.

Tsuchiya Yuki is his wife and their relationship is initially strained, as he feels she might prefer Toudou Sei over him. To his confusion he gets jealous of this and harasses the both of them. As he deals with them more, Yuki will confess her love for Kuon. This can end in multiple ways: either they grow old together, they seemingly get frozen to stay together or he gets her pregnant before her dead and she considers her child a reincarnation of him.

His relationship with his nurse, Yagami Keiko, is an odd one. She is the only nurse that can stand him and is willing to wear the period accurate clothes (she actually likes it). Her angelic like behaviour upsets him greatly as he feels everyone must have a bad side. She tries her best to treat him, but he humiliates her at every step. At one point she considers quitting, but has grown to love him and her heartfelt outpouring melts his heart as he finally agrees to treatment with her by his side. A joke ending has her modify his body to beat the illness. He becomes immortal in the process and she then wants to fight the bad guys with him.

Anzai Ayaka is one of his maids and one of the few willing people in the mansion. Her events mostly just focus on her doing things she finds pleasurable (sex). Her endings sees her leave the mansion only to be stolen back by Kuon. Depending on which route, she either watches him die and takes his money, leaves him be without taking the money (Yuki helps him) or she helps him and lives out a peaceful live in Switzerland with him.

Tashiro Hozumi is another maid. She gets bullied by Kuon as he can't help himself. During the game she turns out to be with child and Kuon is the father. Depending on the route she either commits suicide, kills Kuon or becomes his mistress with his child. Some joke endings are them having a loving relationship and 2 blackmail endings after Kuon did something silly.

His interactions with Kisaragi Katsura initially happen through his work. He takes an interest in her due to her ambition and hope. This either makes him want to crush it or help her. The results of this are either lots of humiliating sex leading to her run away or his help getting her out of the idol business and into an actual singing career. In the good ending she is quite succesfull and Kuon dies just as he sends her off for her Budokan concert.

He acquires Kagami Sayo through a deal with a company chairman about his department store. The young girl can either be cared for by Kuon or by Tsuchiya Sera. If done by Kuon, she has a hard time fitting in. This either leads to her being sent back as she cries for her dad or Kuon fully adopting her and actually trying to raise her with success. The Sera has her quickly become friends with the brother and sister and they move away to live a peaceful life in Switzerland.