It's Actually Not Easy Wanting to be a Supporting Male Lead - Chapter 2.3

Traversing to a parallel World, Shinji Kamihara discovers a mysterious notebook called the 'Chronicles Of Urban Legends'.By writing urban legends in its pages, he can bring them to life in the real world. In this Japan, many of the urban legends from his previous life are absent—Hanako-san of the Restroom, Hell Girl, Sadako’s videotape, the Eight-Foot Woman, Mary’s phone call, the Seiryūji Tunnel, the Gaze from the Cracks, Tengu Elementary…“Let me unleash a pandemonium of Monsters and Ghosts upon this World!”

Urban love story. Chase them if you like them ah.

- Description from Novelupdates

When a boy in a medieval fantasy world wakes up with the memories of his past life, he discovers a secret buried deep within his mind—a highly advanced AI companion. This AI, a relic of his previous existence, holds the knowledge of a futuristic world filled with technology, science, and innovation.Armed with this unprecedented advantage, the boy embarks on an extraordinary journey to transform his medieval surroundings into a thriving futuristic utopia. From reinventing agriculture to creating advanced cities, he introduces ideas far beyond the comprehension of his peers. But his vision isn't without challenges—power-hungry nobles, skeptical commoners, and ancient magical forces stand in his way.