One common way is through extreme emotional growth. When Naruto experiences a profound emotional event, like finally coming to terms with his father's sacrifice in a more in - depth way, it can unlock new levels of power within him. His chakra control might improve, and he could access more of the Nine - Tails' power in a more stable and efficient manner.
Another way is by obtaining new power sources. In fanfiction, Naruto might come across a powerful artifact or be blessed by a god - like being, which gives him a significant power boost and helps him level up. This could lead to him having new abilities or enhancing his existing ones like his Rasengan.
The translation of 'a monster who levels up novel' might be 'A Novel of a Monster's Progression in Levels'. It's important to note that translation can be flexible and influenced by various factors such as the genre and intended audience of the novel.
In Dress Up Time Princess Side Stories, unlocking all levels often depends on your progress in the main storylines as well. If you fully engage with the main quests, it can open up new side - story levels. Also, keep an eye on in - game events. They may offer special opportunities to unlock levels more quickly, like by completing event - specific tasks or challenges.