Primary

• Austin O'Brien Best friend of Jim Crocodile Cook
• Austin O'Brien Friend of Juudai Yuuki

Extended

• Jim Crocodile Cook Best friend of Austin O'Brien
• Jim Crocodile Cook Friend of Juudai Yuuki
• Jim Crocodile Cook Friend of Asuka Tenjouin
• Jim Crocodile Cook Friend of Tyranno Kenzan
• Juudai Yuuki Friend of Asuka Tenjouin
• Juudai Yuuki Former Enemy of Yubel
• Juudai Yuuki Rival of Jun Manjoume