Shalba harbored an immense hatred for Issei after he defeated him in his Juggernaut Drive. Issei also disliked Shalba for his past actions towards Asia. Because of Shalba's growing insanity and his viewing Ophis as merely a tool to raise his own power, Issei's hatred towards him only grows stronger. When Shalba viewed the world that had rejected him and tries to destroy the underworld using Bandersnatch and Jabberwocky, Issei recognizes that he has basically gone insane and outright kills him to save Ophis. This would make Shalba the first person Issei himself has ever actually killed. Ironically Shalba managed to use Samael's poison to finish Issei off as well but, unfortunately for Shalba, Issei's soul survived despite his body being destroyed and would later receive a new body.