Business
Nana and Hachi, after learning about Shin's job
One of Yazawa Ai's quirks about her mangas is that the characters always have something to say that you would least except. For Shin, it's his job as a Host. Basically, Shin sleeps with girls for money. Because he doesn't have a home to return to, he considers the job practical because he gets money and a place to stay at the same time.
Because I have no life, I went through the manga again in my spare time and recorded the names of all of Shin's "customers", as told from chapter 8.
Name: Mayumi
Apperance: None, but she was mentioned in chapter 9. Shin waits outside of the cafe that Shouji works at with Nana and Hachi while complaining about the weather. I remember this scene because after Shin gets a phone call from this girl and decides to leave, Nana starts to lecture him on the reputation of Blast. XD Hachi then cuts in and tries to be more "maternal" and comforts him on his imaginary stepmother while failing at her role.
Name: Reira (Layla)
Apperance: Reira first appears in volume 2 on stage, but she doesn't interact with Shin until Volume six (ch 17) when Yasu takes Shin and Noubu backstage to Trapnest after their mahjong tournament. Yasu leaves early, so he tells Shin to tell Reira that she did a good job. When Shin approached her, Reira gasped out at how handsome Shin was and asked if he would like to play with her. Shin takes it semi-seriously and tells her that he's expensive (100,000 yen). Later on in the chapter, Reira actually finds Shin in a bar and hands him 100,000 yen in cash.
Name: Ryouko
Apperance: Chapter 20. I'm actually not very sure of Ryouko's relationship with Shin. All we know is that in chapter 20, Shin walks into the kitchen in a bathrobe and is greated by Ryouko (who I had mistaken for Reira at first) who was making a drink. They sit down and Ryouko tells Shin that she's leaving for the states again while they're eating and Shin mentions that "from this angle, she really doens't look like you" before asking her for more food. Later on in the manga, Shin tells Yasu that Ryouko the woman who raised him, which Yasu knows is a lie because Shin has no mother. We're never told if Ryouko is one of Shin's customers, or a relative.
Name: Keiko
Apperance: Chapter 24. The only reason I actually remember this is because Shin mentions something about how "Keiko is awfully sadisitic" before he leaves. At the same time, Yasu was asking for Shin's father's permission to sign their record contract (because Shin's 15 and underaged) while his father replies that he doesn't care because she's never loved Shin. I thought it was sad because the next panel was a picture of Shin in bed with a girl (Keiko I persume) while snuggled against her when he slept. Dx