The law of Fiction: Harem in the fiction world - Chapter 1 Ch 0: Character Information And Images

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

A college student, accidentally reborn into the world of Naruto, becomes a member of Uchiha who is destined to be exterminated.

In this cruel ninja world, in the face of endless wars and exclusion from the village, what will Uchiha Qing do?

PS: Later in the book, the protagonist will develop a system of immortal cultivation. Cultivating Immortals in the Ninja World, have you seen it?

- Description from novelbuddy

Arakawa Kouki is reincarnated to a Japan with a different history than the Japan he knows with the memories of his previous life still intact. Kouki was discouraged, “Aren’t reincarnation stories supposed to be at some fantasy world filled with swords, magic and elves?!”

“Love Tripped Into My Room: I Just Wanted Peace, Not Panties”Kaito Tenma just wanted a normal life. Wake up, eat toast, avoid drama, and maybe—just maybe—confess to his beautiful, blunt childhood friend, Riko.But fate sucker-punches that dream into space when a half-naked girl crashes through his ceiling and declares his room as her new home. Now he’s living with Yuna, a mysterious (and dangerously clingy) bombshell who thinks clothing is optional and personal space is a myth.From lewd accidents to jealousy-fueled misunderstandings, Kaito’s life spirals into a wild, hilarious mess of high school chaos, horny misunderstandings, and girls who seem way too interested in ruining his peace.He didn’t ask for a harem. He didn’t ask for trouble. But trouble keeps tripping into his life—one girl at a time.