fukushuu wo koinegau saikyou yuusha wa yami no chikara de senmetsu musou suru

Fukushuu wo Koinegau Saikyou Yuusha wa, Yami no Chikara de Senmetsu Musou Suru
Unofficial English title: The Dark Massacre of the Vengeful Hero
Literal English title as seen on cover pages: The strongest brave who craves for revenge, extinguish with the power of darkness

Light novel authored by Ononata Manimani and character design by Araya; manga illustrated by Sakamoto Akira.