Skeleton Knight, in Another World - Chapter 2Volume 6 -

When The Cute Kunoichis Spied on Their Teacher's Secret is a light novel written by Kazuma Kamachi and illustrated by Ryuushi Tajima.

The story takes place in a world where Japan never ended their isolationist phase, and agents from foreign powers are always threatening to steal the country's advanced technology. In order to combat this threat there has been a resurgence of ninjas that use Strategic Martial Arts, techniques that combine cutting-edge modern technology with a traditional foundation of martial arts and ninjutsu. The story follows Souha Sugiyado, a 17-year old ninja instructor and former ninja prodigy who was forced to retire from active duty by the wounds he suffered in his last mission. Souha's four students are all kunoichi who have all gained the rank of Elite Ninja, the highest official rank available to ninja. However, one day two Shogunate ninja approach him with the news that his four students have gone rogue and have stolen a portable modular nuclear reactor, and thus they ask for his help in bringing his students to justice.

Five years ago, humanity’s strongest Tower Climber was betrayed at the peak of his conquest.Rael Arden, known only by his codename Phantom, was the silent genius who cleared impossible floors, crushed monsters with forbidden magic, and shaped the rules of Tower exploration. No one had ever seen his real face—yet his legend was feared across the world.But at the Tower’s summit, the teammates he carried to glory stabbed him in the back. For power. For godhood. For fear of what he might become.They thought he died.They were wrong.Reincarnated in secret, Rael awakens in a modern world that’s on the edge of collapse. Dungeons bleed into cities. Monsters evolve. The Tower is no longer just a gate—it’s infecting the world. And the very ones who betrayed him now rule from the shadows, hiding behind titles, guilds, and lies.But Rael isn’t alone. His soul split across hidden clone bodies, each designed to infiltrate, gather information, and prepare for war. As each clone reawakens, his power grows—and so does his rage.With him are three women tied to his fate:Selene, the shadow rogue who never betrayed him.Lyra, a curious researcher drawn to the legend of the Phantom.Aeris, the sword saint who still mourns his death… and may not be as loyal to the enemy as she seems.Now, Rael hunts the seven betrayers who destroyed his past.One by one, they will fall.But revenge is just the beginning.Because deep within the Tower, something else is waking—an ancient force that even Rael feared. And this time, the world may not survive unless the Phantom reigns again.

After breaking up with his girlfriend, he accidentally acquired a genius system and rose from there against the heavens, becoming invincible..

- Description from Novelupdates

Gripes have their origins and debts have their creditors. We haven’t crossed each other in days past or present, nor formed any grudges. I am but duty-bound to carry this out, so apologies in advance!

In his past life, Yang Chen was a gentle person who was oppressed for his whole life.

Now that he’s reborn, he chose to become an executioner and severs ties and grudges with his executioner’s blade, killing all that climb onto the Immortal Executioner’s Platform!

Heads will roll! Humans’ in the human realm, demons’ in the demon realm, devils’ in the devil realm and immortals’ in the immortal realm!