A brief description of the manga Road to Kingdom:
Here is the story of a young servant gladiator within an underground arena. He does not understand about his past or how he got to where he is, just that his title is Aegir, he is powerful.
1 afternoon he kills the boss and also leaks the stadium, joining a group of mercenaries as a fresh recruit. After studying that Aegir just knows how to kill, Lucy allows him stay at her residence, teaching and caring for him.
Two years pass, and also on the afternoon of Aegir’s death, they exchange a promise that when Aegir becomes a king and possesses the territory of Erg woods, he could return and take her as his girl. Making this his own life target, Aegir embark on a trip to be a hero, a king, and discovered his own kingdom.