Omnipotent Sage - Chapter 22: Taiji Hammering Skill

Amidst an ordinary stroll home, Jake is struck on the head by a mysterious object, plunging him into unconsciousness. When he opens his eyes, the world has transformed. Now, reborn into a newborn in a magical realm, Jake grapples with the surreal fusion of past and present. Navigating the challenges of infancy, he discovers latent magical abilities tied to this extraordinary reincarnation. As the threads of his former life intertwine with his newfound existence, Jake must unravel the mysteries of his past to fulfill a destiny that spans realms and confront the enchanting and perilous journey that awaits him.

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!

Having lived a normal life all his life and died without being able to fulfill his desire and when he’s given a task by a god, watch how he takes the protagonists girls while making it hard for the hero.

Ever since an NPC named Shu ChunChun, who had been taken advantage of and used carelessly by the world-hoppers, awakened her consciousness, she knew that the only way to drive out the world-hoppers was to make them fall for her, HARD.

- Description from Novelupdates