Well, it's not really about age. It's more about the characters' feelings and circumstances. Some manhwas might challenge the idea of age and focus on true emotions instead.
The manhwa might show how the monster acquires new skills and abilities as it levels up. It could involve battles, adventures, and interactions with other characters.
It could be that the story hasn't developed enough to bring those people into your character's life. Or perhaps your character has trust issues preventing others from getting close.
It's a touching tale that explores themes of love, friendship, and redemption. You'll follow the characters as they navigate through challenging situations and discover their true selves.
I'm not entirely sure as I haven't read it myself. But generally, light novels often revolve around a central character's journey, so perhaps it's about a character who has no choice but to become a monster for some reason, like to protect someone or achieve a certain goal.