One common theme is adventure. The characters are usually on a journey of exploration in the dungeons, facing unknown creatures and terrains.
The theme of discovery is also prevalent. It could be the discovery of new items, new types of magic or abilities within the dungeon. Also, there is often a sense of danger and the characters have to constantly be on their guard, which adds to the excitement and tension in the story.
Power - up is often seen. As characters face various challenges in the dungeons, they level up or gain new abilities. This is often tied to their academic progress in the academy as well, like learning new magic spells or combat techniques in class and then applying them in the dungeons.
Power - up is also common. The artifacts found in dungeons often grant the characters new abilities or enhance their existing ones. For example, in many novels, a character might find an artifact that gives them super strength or the ability to control magic more effectively. Another important theme is exploration. The dungeons are often full of mysteries, and the process of exploring them and uncovering their secrets is a big part of the story. There are usually hidden rooms, dangerous traps, and rare artifacts waiting to be discovered.
Survival is another key theme. Dungeons are usually full of dangerous monsters and traps, so the characters need to find ways to stay alive. For example, in 'DanMachi', Bell has to constantly improve his skills to survive the perils of the dungeon.
Another good 'dungeon dive light novel' is 'Grimgar of Fantasy and Ash'. It focuses on a group of people who find themselves in a strange world and have to explore dungeons to survive. The novel does a great job of portraying the characters' growth and the challenges they face in the dungeons.
One common theme is resource management. Characters need to gather resources to build and upgrade their defenses in the dungeon. For example, in 'The Rising of the Shield Hero', the protagonist has to carefully manage his limited resources to create better shields and fortifications.
Power progression is a common theme. As the dungeon is built, the owner or the related characters gain more power. Another theme is resource management. Gathering resources to build and upgrade the dungeon is crucial in these novels. For example, in 'Dungeon Defense', the protagonist constantly has to think about how to get more resources for his dungeon.
I'm not entirely sure as I haven't read the whole novel yet, but from what I've heard, the main characters are likely to be brave and adventurous. They must be if they're aiming for the deepest level of the dungeon.
In 'a harem in a fantasy world dungeon light novel', the theme of mystery is common. The dungeon itself is full of mysteries - what lies in the deeper levels, what kind of creatures or treasures are there? Also, the theme of loyalty. The members of the harem may show loyalty to the main character in different situations. And finally, the theme of competition. There could be competition among the harem members for the main character's attention or for resources in the dungeon.
One common theme could be adventure. The fantasy world dungeon setting implies exploration and facing various challenges. Another theme might be relationship building within the harem. Characters in the harem may have different personalities and backstories, and the protagonist has to navigate these complex relationships. Also, power progression is likely a theme as the characters often need to grow stronger to survive in the dungeon and deal with any threats that come their way.
Power management is a common theme. The protagonist as a dungeon master has to manage the power of the creatures in the dungeon. For example, in 'Overlord', the main character has to balance the power levels of his various minions.