MTL - Assassin’s Chronicle - Chapter 5 uninvited guest

“I turned into a young dragon and was captured and raised by an Evil Dragon. As we spent more time together, I noticed that the way the Evil Dragon looked at me started to become increasingly odd. It seemed... he was raising me as if I were his wife!” Princess Lucia, transformed into a young dragon, wrote down her discovery with trembling hands in her notebook.

Zeke Draker,The first failure to awaken among the direct descendants of the Dragonslayer family.Expelled from his family for possessing the talent of a Healer instead of a swordsman.Zeke struggled desperately to become stronger, only to face a miserable death.At the moment of his death, strange letters appeared before his eyes.[The soul of the Elder Dragon is engraved into the spirit of the one who possesses will.][An irrevocable and promised power is activated.]When he regained consciousness, he opened his eyes twenty years in the past, in the family that had abandoned him.“If I can become stronger, I will use anything at my disposal.”A new awakening with an immortal power.The legend of a Dragonslayer with a different class begins.

The prosperity is about to come to an end, and the poor boy quietly rises.

Traveling across time and space, seek the leader of the world.

- Description from novelbuddy

A story about a traveler who crossed into a parallel universe, relying on his Proficiency ability to continuously grind experience and become stronger.