Abyss of Dual Cultivation: Goddess's Lust system - Chapter 74

He Lang died by his own hands for the sake of his imperial younger brother’s ambition, whom he loved. He was offered to be reborn in exchange for giving up his past romantic feelings. Reborn without the burden of his romantic feelings, he brings with him a manual to new worlds. He wholeheartedly followed the instructions of the manual to complete the tasks, not knowing that the originally slag gong was blackening…
He pleaded to his affectionate Emperor brother to release him, he pleaded to the paranoid prisoner next door, but until the end he remained baffled.
In the end, he discovered that the full name of the manual was – “Slag Shou Cultivating Manual”
Σ (っ ° ° °;) っ!

- Description from Novelupdates

The so-called 『Enjoy the Human Lives Show Humans Sent to Another World With a Cheat』was trending amongst the Gods. Kanbara Kanata, one of the chosen humans ended up incurring the Evil God’s wrath and as a result, was sent to the worst dungeon,《Cocytus》. But, in a place where he was supposed to lose his life, he met Lunaère, a self-proclaimed misanthropic immortal girl. He was saved by her, who then decided to train him ’till he could at least protect himself.「Master, I think… I’ve become strong enough.」「It’s Not enough! Erm, outside of this dungeon is a dangerous place you know!」「Seriously!? More dangerous than this place…」This is the story of Kanata who was trained by his master, who easily succumbed to loneliness, till he became the greatest hero of legend, and yet was unaware of it.

After coming out of a tunnel… it was pitch dark.