Primary

• Masaomi Kida Best friend of Mikado Ryuugamine
• Masaomi Kida Former boyfriend of Saki Mikajima

Extended

• Mikado Ryuugamine Best friend of Masaomi Kida
• Mikado Ryuugamine In love with Anri Sonohara
• Saki Mikajima Former girlfriend of Masaomi Kida