社会の底辺に沈む中年社畜おじさん、末期の病を宣告されSSS級ダンジョンで死を選んだところ……最強の伝説モンスターと融合し、超絶強者となる！ (Associated Names)

In the depths of society, a middle-aged salaryman, worn down by the grind of life, faces the grim announcement of a terminal illness. Faced with despair, he chooses to enter an SSS-class dungeon, choosing death as an escape. However, an unexpected twist awaits him: he fuses with a legendary monster of unparalleled strength, transforming him…