The Strongest Wizard Becomes a Countryside Guardsman After Taking an Arrow to the Knee - Chapter 452 - Giscard, the Hero

This is a story about the protagonist getting the system, going crazy in the biochemical apocalypse, producing aircraft and tanks, destroying zombies, saving good people and killing bad people.

- Description from novelbuddy

Young Chen Xiang had a fateful encounter with a goddess & demoness and received their peerless heritage, divine pulses, ultimate martial arts, and transcendent alchemy techniques, which gave him an easy ride in his journey of cultivation.

When hungry, he refines some spirit pills to eat as snack, when lonely he flirts with the goddesses, when bored he teases those martial artists who came to beg for spirit pills, when tired he lets his beautiful wives massage him.

- Description from Novelupdates

After the brutal loss of his beloved grandfather, Liam Hunter embarks on a harrowing journey into the heart of the Dark Forest, known as the Forest of Kyrell, with a singular goal: to gain the strength necessary to honor his grandfather’s memory and to never lose anyone dear to him again. At just ten years old, Liam is thrust into a world of darkness and malevolence, where he endures four grueling years of training and transformation. In this shadowy realm, he is reborn as a fierce warrior, driven by a relentless desire to eradicate every demon and ultimately confront the Demon King, Emrys himself. To achieve his formidable goal, Liam must forsake any emotional connections that could weaken his resolve. The once vibrant and joyful boy is transformed by his trials into a cold and unfeeling combatant, hardened by the harsh realities of his quest. This is the story of Liam Hunter—the last wielder of dark magic—whose journey through darkness and sacrifice will shape him into a force of vengeance and resolve.

This is a story of a man named Kim Sae-Jin, who one day, inexplicably wakes up as a Monster. Follow him and his perilous journey to get his life back as a Human, all the while growing even more versatile as a Monster in the process. This should be… complicated, somewhat.