Elf Tensei Kara no Cheat Kenkoku-ki - Chapter 12Book 3: -2: The Gates of Hell

Arthur was a weak and cowardly boy who lacked the power to protect anyone—a truth brutally demonstrated when his parents were massacred while defending him during a Gate outbreak. As the sole survivor, Arthur spent weeks believing his life was over. When intense chest pains began, he assumed he'd been infected with corruption by the void creature that killed his parents and was merely waiting for death.What Arthur didn't expect was that these sensations actually signaled his Realm Core forming. In two months' time, he would be forcefully transported to the next realm and awaken new powers, becoming one of the world-renowned “Chosen” who protect humanity from Gate outbreaks. Now Arthur must rise through the heights of power, climbing each of the seven realms in hopes of saving his world... or does he?

The mortal body, metamorphosis, longevity, immortality, and eternal life. These five realms, step by step, reveal themselves in front of you. As a normal person, how can one try step by step to reach and open the door to eternal life?

Between the heaven and the earth lies the mortal body, the mysteries of metamorphosis, freedom of longevity, the power of immortality, and the hope of eternal life. A story filled with endless new magic, a new world of immortal styles, people, demons, gods, fairies, magic, kings and emperors. A world of love and hatred, revenge, and mystical battle, all in “Eternal Life.”

- Description from Novelupdates

The main character is reborn as a character from a game he played in his previous life. This character falls into ruin along with the villainess, spending the last of their years together. A man named Kururi Helan.

In her previous life, Yvonne Taylor died with hatred. Her stepsister burned her face with sulfuric acid, and her father was brutally murdered by her stepmother. Even Zachary Leinster, her father's best friend and the man who loved her the most, died trying to save her.Yvonne is miraculously reborn and begins her revenge.When she comes back, she is no longer the playful girl everyone knew. In order to take revenge, she applies for a prestigious school, majors in business, caters for her stepmother, and even... marries Zachary Leinster, her father's business competitor and ten years her senior.