Reincarnated Sword Emperor

Across the Nine Heavens and Ten Lands stand seven ancient forbidden grounds, teeming with baleful energy, where gods and demons give them a wide berth. They are deadly wastelands that strike fear into every cultivator.

Everyone knows: no one ever returns from within a forbidden ground.

No one knows that, deep inside the seven forbidden grounds, a young guardian of the realms has slept for ages, keeping watch over them.

The protagonist slept for a hundred thousand years, using his soul to suppress the demonic energy of the heavens and the outer-realm fiends. After exhausting his cultivation and becoming mortal, he is accidentally awakened by a female disciple from a small sect at the foot of the mountain.