Valerian, The Legendary - Chapter 104

The eldest daughter of the Li family is beautiful and sassy, ​​she took space materials to flee famine, and after going through many difficulties in war, disease and epidemic, she united with her family to regain the glory and harvested a beautiful boy.

- Description from novelbuddy

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!”

“Why don’t they think about training to grow stronger during a time when just breathing makes you stronger?”After possessing someone, he decided to silently train to become a great mage.“Did it appear?”[You have acquired the All-Attribute Body (Fire, Water, Wind, Earth, Wood, Electricity, Light, Darkness).][You have acquired the highest-grade elixir, Dragon’s Essence (SSS).]……Let’s take a slightly different path to growth from others.

An ordinary (?) grandfather, Choi Chuntaek. In an effort to protect his granddaughter, he started the virtual reality game 'Arkstar.'

Then... he accidentally obtained a legendary class?