Without having read a specific 'circlet girl light novel', it's hard to say exactly. But generally, in a light novel, the 'circlet' could be a significant symbol. It might represent something about the girl's status, power, or identity within the story. Maybe she's a princess or a magical being and the circlet is a mark of her specialness.
The main character in <<The Immortal of the Other World>> had his dantian broken and became a cripple because of a woman. He was later saved by the Immortal of Qingxuan. I can recommend this book to you. I hope you will like my recommendation. Muah ~😗😋
If you have more details about the 'circlet girl light novel', such as the genre it might belong to (for example, fantasy, romance, etc.), or any other elements like the author's name or the setting of the story, it would be much easier to recommend. Some light novels are also adapted from other media like anime or manga, so if it has such a connection, that could also be a clue to find it.
The beaded circlet could be a symbol of continuity in the never - ending story. It might represent an unbroken cycle, like the eternal nature of the story itself.
The word "oil" above Selaiya's head referred to the Ninja ID of the famous Ninja Selaiya in Naruto. He had given himself this ID to represent his identity and experience as a ninja. In the ninja world, IDs were usually a symbol of a person's identity and profession. The ID "Oil" meant that he was a ninja who used Oil (Oil Escape). Oil was a powerful ninjutsu that could create all kinds of liquid attacks, including ointment, oil candles, oil lamps, and so on. Kirai became one of the famous ninjas among Naruto due to his superb ninjutsu and combat experience.