Primary

• Shizuo Heiwajima Older Brother of Kasuka Heiwajima
• Shizuo Heiwajima dislikes Izaya Orihara
• Shizuo Heiwajima Friend of Tom Tanaka

Extended

• Izaya Orihara Older Brother of Kururi Orihara
• Izaya Orihara Older Brother of Mairu Orihara
• Izaya Orihara In love with Shizuo Heiwajima
• Kasuka Heiwajima Younger Brother of Shizuo Heiwajima