The World's Least Interesting Master Swordsman: Volume 1

Sansui Shirokuro was a young man with an old man's name, until a divine mistake ended his life and sent him to a fantasy world. After five centuries of solitary sword practice, he is finally thrust into the mortal realm with a mission to raise a child. Now, this incredibly skilled but unassuming swordsman must navigate the complexities of the world alongside a haughty noblewoman and her bodyguard.