MTL - The Roots of Manga - ~ make up tomorrow

This world is sick; both Immortals and mortals suffer from a stubborn ailment known as Longevity.Under the influence of Immortality, various Cultivation Techniques evolve rapidly in grotesque and inexplicable directions.[Fetal Period: A baby is born with shriveled, powerless limbs.][Childhood: After 20 years, the Internal Organs completely decay.][Weak Crown Period: At 50 years, the flesh dries and withers.][Thirty Years Old Stage: After 100 years, the blood runs dry and gives birth to mutations.]I am an Immortal Seeker, and also one seeking survival.

I became a scientist for an evil organization.…But I’m too competent.

Yuka, reborn as the daughter of the universe's richest man, tries to live a simple life. She gets a big shock when she has to join Union University of the Alliance because of government rules.In university, Yuka picks an easy major, hoping to keep a low profile. But her plan doesn't work. She keeps facing tough situations that show off her smart mind and strong skills. Yuka tries hard to live normally but keeps getting pulled into extraordinary accidents.This is the story about how Yuka grows. It's about her trying to hide her real identity while dealing with a world that always challenges her.

(Third Person Limited PoV.)Betrayed by his fiancée, mocked by his siblings, and disowned by his family—that was Lev’s fate.Even when he regained memories of his life on Earth, where he realized that his world was strikingly similar to his favorite novel, it still didn’t help him change anything.How could it be?Because the protagonist of the story had already achieved his happy ending—gaining a beautiful wife and living a blissful life. Meanwhile, the world continued to move forward.What do people usually do with a novel that has ended? They tend to stop caring about the world within it, even if it falls into ruin, especially if the novel isn’t particularly popular.The world Lev Razanov lived in shared a similar fate—it was destroyed.[Hero’s System successfully installed.][Critical condition detected.][Do you wish to return to the past?]Lev was given a chance to return to a time when the story of his favorite novel had just begun.Although he was destined to become an extra villain—a pawn of the pawns serving the real villain, he vowed to end the lives of anyone who had caused him suffering: his siblings, his fiancée, the main character, or anyone else.[Hero’s System inherits your desire from your life on Earth—the desire to do good.]“Who said killing your enemies is an evil act?”