Zero no Tsukaima - Volume 2 Chapter 3

An ordinary student accidentally traveled into an other universe and became the king of a small kingdom. He had gotten a “Cheating Code” of life and was able to complete something extraordinary. This is the story about a king that was able to conquer continents and leave behind him an ultimate legend that will be recited between every generation to come.

Qiao Zhenzhen spent a lifetime, only to later realise that she was the true heroine of a novel. According to the original plot, her life was supposed to be smooth sailing and blissful. But the envious transmigrated second female lead played her cards step by step, and took everything away from her!

After experiencing the divorce of her parents, and miserably failing the college entrance examination, she gets kidnapped along with her little follower of a male lead, Chi Shen. In the end, she came out as the only survivor.

Everyone believed that this was a blessing in disguise, not only was her life saved, but the pervert stalking her for the last three years was also gone! A freak like Chi Shen, who had a weird and eccentric personality, always stank of fish and grease, was better off dead. Everyone said that she ought to be grateful, but none of them knew he died protecting her.
Before he took his last breath, his dying words were-

“Don’t be afraid of me.”

That sentence, mixed with the smell of greasy fish and blood, flashed in her dreams every night for the next decade.

Reborn back into the senior year of her highschool, she walked to the youth in the corner, and in front of everyone’s eyes-

“Don’t hideaway in the dark if you don’t want me to be afraid of you.” The youth pursed his lips, his pale face steadily losing color.

Qiao Zhenzhen smiled: Be nice to me, and I shall allow you to stalk~

- Description from Novelupdates

Kai was a 17-year-old dropout. A NEET. A background character in real life with nothing to his name but bitterness, novels, and guilt. After his parents died, he gave up on the world. People were fake. Dreams were pointless. And that one novel he kept reading? He hated it especially the main character, June. Perfect, noble, always standing tall. Everything Kai wasn’t.Then, one night, a voice asked: “What if you did meet June?”He said yes, half-asleep and half-mocking.Now he’s trapped in the novel. Isikeid. But he’s not June. He’s not a hero. He’s not even in the main cast.He’s an extra in the background of a world he knows too well and he’s had enough of watching things play out the same way. This time, he’s going to change everything. Whether the world likes it or not.

In a world teeming with Titans, Colossals, Gigantic Monsters and Kaiju's, Erian who reincarnated makes his living collecting scraps of low-grade Defective Genetic Serum, realised he transmigrated along with his system.

Follow Erian as he grows to become the strongest Disaster Grade Titan with the help of his Titan System!