[Hazawa Koichi × Kusui Aruta] Gakuen Souken Embu Vol.2 | Erotic Dance of the Campus Dual Blades
[Hazawa Koichi × Pierre Yoshio] Makai Shoujo R'lyeh Lulu Vol.2 [Digital]
[Hazawa Koichi × Kawagishi Keitarou] Thunder Claps! Ingoku no Shi Tenshi
[Hazawa Koichi, Kannazuki Nem] Seitokaichou o Nugasou!
[Hazawa Kouichi, R-Ex] Kenran! Teito Shoujo Tanteidan - Akai Bouryaku wo Ute!