Yumi is a close friend of Kazuma Kiryu and Akira Nishikiyama, both of whom she grew up with at Sunflower Orphanage. In order to stay close to Kazuma Kiryu, who is her childhood crush, she left for Kamurocho and began working at the bar Serena as a hostess. If you know about Japanese culture then the hostess is women who talk and drink with customers. They are not prostitute. Kiryu was informed that Yumi has been kidnapped by Patriarch Dojima. By the time Kiryu arrived at the scene, Nishikiyama was already there. He murdered Patriarch Dojima in order to protect Yumi (who is his childhood friend and crush) and Yumi went into a deep shock. Knowing Nishikiyama's younger sister was in a hospital bed, Kiryu volunteered to take the fall for Nishikiyama, allowing the other two to escape. Yumi loses her memory as a result of the trauma she experiences at the hands of Sohei Dojima, who is boss of Dojima clan and Kiryu, and disappears from the hospital shortly after being admitted. She marries Kyohei Jingu, but shortly after their daughter, Haruka Sawamura's birth, Jingu leaves Yumi for a more profitable marriage to the Prime Minister's daughter. 10 years later, now 37 years old and after his release in December 2005, Kiryu returned to Kamurocho for answers and was told to search for Yumi. After regained memory, she has a "Queen of the Night" lotus tattoo on her chest that she states symbolizes her love for Kiryu, from it she wish she will never forget Kiryu. There is the quote of Yumi at the end "I got this tattoo... The queen of the night. Whether it was one night... Or even just one glance. I wanted to see you one more, Kazuma. And my wish... was granted."... Man, it's hurt... SO SO MUCH.
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