From 0 To The World's One and Only Dimensional Walker

What happens when you take a good guy, give him a shitty life and make him live through a trash life with a moderate 9-5 job? you make a suicidal maniac who ends up becoming the worlds most inevitable calamity. From being raised in a poor lifestyle to living through a poor one himself, Hiroshi Takumi's life was bound to end..and if it didn't he would have done it himself. But who would have thought that his death was simply just a reboot, a restart button or better yet a respawn input that flushed away all his past or future mistakes and gave him a new fresh taste of life in his past self with awesome dimensional breaking abilities?