Shijou Saikyou no Deshi Kenichi OVA

KenIchi: The Mightiest Disciple OVA, 史上最強の弟子ケンイチ OVA, History's Strongest Disciple Kenichi OVA, Shijou Saikyou no Deshi Kenichi: Yami no Shuugeki

OVAs of History's Strongest Disciple Kenichi bundled with volumes 46, 47, 49, 53, 54, 55, & 56 of the manga.