Earthly swordsmanship
The eldest grandson of waste firewood, who can't find death, but becomes one with the perennial soul who has crossed over. Since then, the eldest grandson of the young man has walked in the world with a knife.
Forge a knife in the world, and groan alone in the hustle and bustle. This knife carries hatred and hope, and this knife represents blood and responsibility.
Let's look at the turbulence of the Kyushu continent, and the young eldest grandson turns into a dragon and groans.