Tensei Shitara Slime Datta Ken (WN) - Chapter 327

"When will people understand.... I'm only half insane?"

An Imperial Scholar by day. An assassin by night.The World of Cultivation has changed.Elemental Mancers. Flux Mancers. Spirit Mancers. Soul Mancers.Raining down fire and splitting oceans. Destroying mountains with a single stomp and calming skies with a glance. Controlling the tides of Karma, while wielding the souls of others like a puppeteer tugging on the Lines of Fate.The most mysterious of them all were Spirit Mancers, a truth that Theron was more than intimately familiar with. Due to one's Tribulation, his life was turned upside down. His family, his rage, his somber sadness becoming nothing more than Bad Karma's fuel for a madman.He was once a gentle young man, a non-combative Water Mancer who wanted nothing more than to read his novels to the sound of the rain and one day become an Imperial Scholar.But now...Everything had changed.He donned a cloak in the silent night as the clouds above gathered. Pulling its hood over his chilling blue eyes, he stalked off into the darkness.The first droplets fell.He would become the nightmare of his enemies, the blade hidden in the shadows of Heaven's tears.The River of the Night.

The formless ancient world was infested with despicable demons. They hunted and feasted on mankind, keeping the human civilization constantly in a weak and suppressed state.

During the first known year, a magical mountain descended into the world from the realm of the Gods. Carved on this enormous mountain was a message: ‘Heaven Prevails’…

After the Grand Descent, a name that was given to the descending of the mountain, the Three Great Sages made their ways to Mystic Mountain where they learned to harvest what we now call magic, establishing the Mystic Cults and eighty-one sacred shrines to help aid mankind with the cult’s mystic powers against the eternal fight to the death with demons.

- Description from Novelupdates

The protagonist, Winnie (文尼), confesses his love to his childhood friend—the princess he’s been secretly in love with for years—but is brutally rejected in public. His heart shatters, he’s humiliated and ridiculed, and he collapses unconscious. When he wakes up, he vaguely remembers his past life’s memories and realizes he has transmigrated into the world of an otome game he played before. At first, he’s thrilled, thinking, “Nice! I must have been reincarnated as a villainous side character who disrupts the protagonist’s romance, right?” But then… surprise! He’s not just the villain—he’s the “Saintess”!