After infusing the darkness Cosmo in Koga's body, Amor finds out that he was betrayed by his sister and swears to kill everyone including her. Meanwhile on the Earth, Kiki, Harbinger, Fudo, and Genbu use their Cosmo to send Koga's friends to Mars. As he finally reunites with Saori, Koga is overcome by the darkness Cosmo and possessed by the God of Darkness, Abzu, and kills Amor in one single blow. As the possessed Koga proceeds to kill Athena with his own hands, his friends try to have him return to his senses without success, until Eden stands in his way.