[DROPPED!!!]

At the peak of his power, Klein could not abandon his obsession with immortality. He spent five years on a dubious elixir of immortality, unfortunately, to be transported into a completely different world filled with fantasy races like Elves, dwarves, giants, satyrs, orcs. 

Thankfully, the elixir of immortality wasn't a total flop, as it gave potential greater than the Heaven's Chosen with a slight caveat.

Klein will have to dabble in various paths of cultivation, orthodox and unorthodox, to reach his dream of immortality. But before all that, he needs to escape the wrath of the elves, for accidentally becoming the Dao Companion of their princess. Unfortunately, the task became a lot harder when he didn't even know their language.

Artificial Ascension: A Mage's Guide to Uplifting a Mystic World

A few hours later, after Klein was done recording a whole shelf, someone finally came back to check on him.

"What have you done to my study?" Elanor asked, her eyes wandering to the stacks of books and papers scattered all over the room.

"Sorry, I'll put them back in their place," Klein said and began carrying a stack of leatherbound books back to their rightful place on the shelf.

Elanor rubbed her forehead and came to help him. She sighed in relief, finding none of her books were damaged. "Why did you even open so many of them?"

"I was," he paused, "memorising them."

"Really?" Elanor shot him a flat stare. "You were memorising over two hundred volumes of a book in a single afternoon?"

Elanor's eyes moved to the book still open on the table. "What is the formula for Lightning in a Jar?"

"I'm sorry?" Klein lifted his head to spare her a glance.