The countless dungeons that suddenly appeared on modern Earth have now become a part of everyday life. Yuuto Kurashiki, a young man who has become a hikikomori for some reason, challenges the dungeon to break through the dead end of his life. However, the unique skill given to Yuto was ironically . Not only is it difficult to use, but it also has a huge negative correction to the ability value, which is the lowest and worst failing skill. However, Yuuto soon finds out that this skill has an outrageous potential! https://ncode.syosetu.com/n7575gq/