Primary

• Nishiwaki In love with Yukio Okumura

Extended

• Yukio Okumura Twin Brother of Rin Okumura
• Yukio Okumura Older Version of Yukio Okumura (child)
• Yukio Okumura Half-brother of Amaimon
• Yukio Okumura Half-brother of Mephisto Pheles