Osamu Asada (浅田 修, Asada Osamu) is a 27-year old secretary and manager of Kanae Murota. After meeting her at anti-social organization, he left the group and helped her establish Shan City, while also becoming her lover.
When Mutoh's group arrive at Shan City, he welcomes them and after giving them food, he shows them around, explaining how they are self-sustaining and shows them their tends.
He keeps the schedule of Kanae, informing her when she needs to speak with the deceased and helps and organize everything.
When Shan City is hit by earthquake, Kanae tells him to open the gates and leave the people out. After that, he heads into the basement to free Kunio, but seeing Kite there, he gives him the keys and tells him what route to take to escape.
He goes to look for Kanae and finds her injured after a shootout from people who wanted to take the money from the vault. She tells him they need to take Daichi and reaching his room, they are shocked to see Daichi standing and thanking her mother, but then a rock hits Daichi and kills him. Kunio and Kite then arrive, and Osamu tells him this wasn't his grandchild, but Kunio comments he knew. When they leave, Osamu and Kanae decide to stay there and die.
Osamu comments that Daichi lived a happy life and that he managed to survive until now because he was here. He believes that Daichi's final words meant that he didn't want Kanae to summon him, wanting her to live the remaining of her life for herself. Kanae then tells him they need to survive and Osamu agrees. Some people from the community approach them and explain this is where they belong and since Kanae saved their lives, they want to end it with her. The building then collapses with everyone inside of it.