Sovereign of the Three Realms (WN) - Chapter 2263: Large-Scale Invasions

Every novel has a slag character, the one who decides to abandon the protagonist at his lowest, most helpless point, either because he can’t stand the poor guy’s circumstances or for other reasons. But after the protagonist wins his way in life again, they’re the ones who beg with broken sobs to be taken back.

Still, water once spilled can’t be recovered again.

Yet the unlucky Shen Jiayan has been bound to a Water Recovery* System to do just that.

*water recovery – comes from an idiom that means “spilled water can’t be recovered” (English equivalent: there’s no use crying over spilt milk).

- Description from Novelupdates

A girl who calls herself a demon appeared before a timid student named Fumio Kijima. The girl claims to be a campaign girl from the demon world and she gives him the ability to “summon a room” from nothing but thin air.

At first he doesn’t abuse his power and uses it as a convenient ability in his every day life. But one day he is bullied by his classmates under a false pretext and is made to suffer. In the past he would have wallowed in misery and cried himself to sleep, but now he had a power to call upon.

“I will make them regret it!”

Using his powers to summon his “room”, he begins his era of confinement and brainwashing to achieve his goals.

In a world where the strong prey on the weak and nobles slaughter commoners like insects, Alex was just a weak boy who lost everything to the cruelty of fate.For the sake of revenge, he rose from the ashes, determined to carve his path through a world soaked in blood and betrayal.But there is something the world does not know—something even Alex himself has yet to discover...A power buried deep within his blood, ancient and untamed, waiting to awaken.

Step inside if you dare, but be warned—this is no ordinary shop. Those who enter never leave the same… if they leave at all. A sinister force lurks within, fueled by a dark past and a thirst for revenge. The price? Twelve lives for twelve sins. As officials race to put an end to the bloodshed, the shop’s deadly grip tightens, claiming innocent victims one by one. Will anyone uncover the truth before it's too late? If you crave spine-tingling horror, heart-pounding thrills, and a mystery that refuses to stay buried, this book will haunt you long after the last page.