Extreme Knight - Chapter 502: doppelgänger

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.

With a square halberd in the palm, and a red rabbit and horse under him, nowhere can the world go!

- Description from novelbuddy

The Blood Warrior of the Ungpae Association, who created a sea of blood wherever he went, made the world of the Forces of Evil possible.

The Nine Great Sects and the Six Great Clans joined forces to fight him, but were unable to stop him.

Four Great Warriors, who were Murim’s last hope, appeared.

The four of them fought against the Blood Warrior and eventually defeated him at Mount Song.

The time has come for the legacy of the Blood Warrior to rise once again.

After dying, Chen Heng finds that he has transmigrated to an alternate reality: everything is the same, except the world is now a Wuxia world heavily influenced by martial arts! Not only this, he discovers that he has a Fantasy Simulator, from which he obtains rewards that make him incredibly powerful in his new reality as well. Martial arts, immortal cultivation, and overpowered abilities–all of this begins from a single simulation!