Otome Game no Heroine de Saikyou Survival - Chapter 101

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.

Gu Jin crossed into a novel as the supporting character and best friend of the main female lead, Cheng Xin.

Cheng Xin was frequently surrounded by men of status and quality. As Gu Jin was the female lead’s dearest friend, she doesn’t mind settling for the leftover meager soup if the female lead chose to eat the meat. The two sisters believed they’d enjoy this friendship for a lifetime.

But just as she was ready to latch firmly unto Cheng Xin’s golden thigh, she discovered the body she crossed into had memories of future events beyond the novel’s plot, finding out that her marriage would end in utter failure.

The female lead, Cheng Xin who often quarrelled with the male protagonist would head over to Shao Chong for comfort even though Shao Chong was married to Gu Jin. And after several incidences, Gu Jin advised Shao Chong to have a sense of propriety as her spouse but he told her not to think too much about it, claiming that he only maintained a pure friendship with Cheng Xin.

On the day Gu Jin was kidnapped, her good husband stayed by her cousin’s side and accompanied her to the hospital.

When Gu Jin transmigrated into this new world and learned of the truth, she did not wish to waste this new life as a supporting role for her cousin as the previous soul had done. She’d not live a life as a spectator in someone else’s love story. No. She would be the protagonist of her own romance in this new life.

- Description from Novelupdates

Qinghe County master Gu Sheng died. She had a first class beauty, her name could move the world, but she still lost to the hands of a woman inferior to her. Gu Sheng was only able to understand that she was the antagonist of the heroine after her death, a cannon fodder.

In a pure white space, Gu Sheng was expressionless because of the transmigration.

System: “The heroine must change her fate, must fight against cannon fodder and the passerby to brush a sense of existence. As the master, you are their biggest stone in the way.”

Gu Sheng’s eyes flashed and made a peerless smile, “Then let me see who is the stumbling block that should be trampled and who is the final winner!”

- Description from Novelupdates

After accidentally falling, she actually finds herself bound to a Second Female Lead Counter Attacking System!