Fukushuu o Koinegau Saikyou Yuusha wa, Yami no Chikara de Senmetsu Musou Suru

Raoul, who had defeated the demon king as the strongest hero, should have become the savior of the world. Having his treasured companions and family killed by power-hungry aristocrats, he was executed with false charges brought against him by the princess. Just before his life collapsed, at last, his heart fell into darkness.