Saint Seiya Omega

Yuna, Ryuuhou and Haruto are transported to an unknown dark place and eventually reach a door, which they touch and are all transported to a world of memories. Yuna is on her hometown with her childhood friend before the war, Ryuuhou is on his childhood on Palestra along with his then friend Lynx Mirapolos and Haruto faces his own brother Yoshitomi. All three realize the world they are in is an illusion created by the darkness in their hearts and are at first hesitant to battle, but manage to overcome the darkness and reach the Core of Darkness.