Shikkokutsukai no Saikyou Yuusha: Nakama Zenin ni Uragirareta node Saikyou no Mamono to Kumimasu  

The strongest brave man of the black wizard, The Brave Jet Black Wizard: I Got Betrayed by My Comrades so I United with the Ultimate Monster, The Mightiest Hero of Black: My Party Members Betrayed Me so I'll Stick With The Strongest Monster, 漆黒使いの最強勇者 仲間全員に裏切られたので最強の魔物と組みます, The Strongest Hero: Envoy of Darkness - Betrayed by His Comrades, the Strongest Hero Joins Forces with the Strongest Monster, 漆黒使いの最強勇者　〜仲間全員に裏切られたので最強の魔物と組みます〜

The "Hero of Darkness," known for being the strongest hero ever, believed in his current party members and swore to defeat the Demon Lord with them. However, a tragic event occurred when he was betrayed by the girls he trusted. Despite barely surviving, this incident left him scarred emotionally. He eventually gave up on living and wandered around in search of a way to end his life. While doing so, a single monster appeared before him and asked if it could kill him. Shion, who still had some strength despite losing his powers, agreed to let the monster take his life.

Shikkokutsukai no Saikyou Yuusha: Nakama Zenin ni Uragirareta node Saikyou no Mamono to Kumimasu has been published digitally in English as The Strongest Hero: Envoy of Darkness - Betrayed by His Comrades, the Strongest Hero Joins Forces with the Strongest Monster by Square Enix through Manga UP!