Start by Making a Demon Sword in Demon Slayer

After I was hit by a white truck and killed, a guy who claimed to be the god of the second dimension asked me what system I wanted to have after time travel. I just said that you can become stronger without moving, but... Oh no, they used me to kill people again. Immortal Kawa Genya: Let me protect my brother this time! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.