I'm Scattering IQ to the Protagonist - Volume 1 _2_3_Chapter 25

The Northern Ice Fields had no boundaries.

The Winter Wolves hid within the snow, the Frost Tigers growled incessantly, and the roars of Giants echoed throughout the land. Many species struggled to survive in the icefield. At the same time, a baby White Dragon possessing the power of time broke out of its egg and opened its platinum-colored eyes.

Years later, the legendary Time Dragon appeared, moving freely between the endless past, present, and future.

In her last life, she was miserable and ordinary. This time, she got into the fashion and was reborn in another world. She was still the same person… even with the same body and face. What was the point of reincarnation? A childhood companion? He always pulled her hair and made troubles for her? A handsome boy? The boy never looked at her and was 15 years older than her! A prestigious teacher? The teacher spent his days eating and drinking, coaxed, played tricks, and controlled others… Too scary and better run away? No no no, such a challenging life was bound to be wonderful! Now let me take you back to the 70s and live a fast life!

- Description from Novelupdates

Kusumi Chiharu gets a message one day that he has been selected as a Monster Tamer, and he is prompted to select his first partner. He thinks little of the message until he receives a giant package the following day. He assumes it’s the porn books he ordered, but the huge box ends up containing the unconscious body of a near-naked girl! She’s a ghoul named Zonmi, who intends to fight beside him as his partner.

However, it turns out that other hot girls at his mostly-male high school are also magical entities, and Zonmi may not be the only one who wants to fight by his side!

“Finally, the owner has appeared. You read me.”The Archmage’s legacy, the Book of Truth.Binair Dalheim, a dropout of the Elfenbein Tower, accidentally discovers the Book of Truth.“I will awaken your magical talent. In return, complete me.”The dropout boy, whose dormant talent has been awakened, begins his journey to retrieve the Book of Truth as requested.