(Nearly invincible, with a slow pace at first.) The protagonist is fairly weak in the early stages.
Overworked office worker Ye Chen dies suddenly from working overtime, only to transmigrate into the biggest good-for-nothing in Qingyang Town!
Then he grips his family’s rusty old sword
“I am the Swordslayer, and I once slew thirty-six Immortal Kings!” The sword spirit shatters the seal on his dantian. “They called your Chaos Dao Body a severed meridian? Those fools are blind!”
Three years later, the youth emerges amid a thunderstorm, pointing his sword at the heavens.
Swordslayer drinks blood and rings out, and even the Ninefold Heavenly Tribulation parts for him
“A good-for-nothing with severed meridians? Today, the cultivation world will see a new sun and moon!”
“With this sword, I’ll slay my enemies first, then challenge the Heavenly Dao!”