Jimi na Kensei wa Sore Demo Saikyu desu

Shirokuro Sansui, an ordinary Japanese student, met a premature end due to a careless mistake made by God. As compensation for this divine error, he was offered a chance at reincarnation in another world. Driven by a singular ambition to become the strongest being in existence, Sansui accepted a letter of introduction from God and embarked on a grueling five-hundred-year training regimen under the guidance of a Sage. After centuries of relentless discipline, he finally attained a level of power that would be considered unparalleled by the standards of ordinary people. His long-awaited journey into this new world truly begins when he discovers an abandoned baby near his remote training grounds. Taking the child in, Sansui steps out into society to begin his adventure. Yet, despite possessing overwhelming strength, his demeanor, techniques, and fighting style remain remarkably unrefined and understated. Wielding nothing more than a plain wooden sword, the unassuming Sword Saint sets forth. To the outside world, he appears entirely ordinary, but beneath his modest exterior lies a warrior whose simple approach conceals absolute supremacy.