A powerful mage from a far - off land could be a new addition. She could be on a quest to study the unique magic in the dungeon and ends up getting involved with Bell and the others. Her powerful spells and mysterious background would add a new dynamic to the harem.
An elf archer who has lost her way could be added. She is very skilled in archery and has a deep connection with nature. She gets drawn into the group when they help her find a special plant in the dungeon that she needs for a personal quest. Her calm and collected nature would contrast with some of the more energetic members of the harem.
I'm not entirely sure as I haven't read this part yet. But perhaps there will be some new adventurers joining the group, or some mysterious characters related to the deeper parts of the dungeon.
A plot could revolve around a magic item that is found in the dungeon. This item has the power to grant a wish, but only one. The harem members all have different desires, which causes a lot of tension. Some might want to use it for Bell's benefit, while others have more self - centered wishes. This would lead to a complex web of emotions and decisions within the harem.
Rukia could be in the harem. She has a connection with Ichigo already and her strong personality might be drawn to the power and mystery of Hollow Ichigo. Orihime is also a likely candidate. Her kind and loving nature could be what makes her want to reach out to Hollow Ichigo and be part of his harem.
A human student with latent supernatural powers could be added. This character could befriend Gasper and his harem, and their discovery of their powers could be a major plot point. They might also cause some jealousy within the harem as they get closer to Gasper.
A heroic knight from a medieval - themed anime. He could be transported to the Highschool DxD world and, due to his chivalrous nature, attract the female characters. He might initially be at odds with the devils but eventually form a bond with the main character and become part of the harem as he adapts to the new world.
In such a fanfiction, Princess Bubblegum from Adventure Time could be in the harem. She's intelligent and powerful, and Naruto's unique skills and personality might attract her. Also, Sakura from Naruto could be part of it. Since she has a history with Naruto and in this crossover, she could be part of the group vying for his attention. And Marceline too. Her cool and edgy nature might be drawn to Naruto's heroic side.
Perhaps Naruto, as a god, would start a revolution in the way familias are run in Danmachi. He could promote equality among members based on his own experiences in the Naruto world. His godly powers might also allow him to create new dungeons or modify existing ones for the betterment of the adventurers.
Unfortunately, without having read Danmachi Volume 19 Light Novel in full, it's difficult to name the new characters precisely. But typically, new characters in the series are designed to bring fresh challenges and interactions. They could be powerful adventurers that Bell and his friends have to team up with or compete against, or they could be some strange creatures from the deeper parts of the dungeon with their own motives and behaviors.
One popular 'danmachi harem fanfic' might be those that focus on Bell's adventures with different female characters in new and exciting scenarios. For example, a fanfic could explore Bell's relationship with Hestia in a more in - depth way, showing their daily interactions and how their bond grows stronger. Another type could involve Bell getting involved in a quest with multiple female companions from the Familia, and the fanfic delves into the dynamics between them all.
Potential members could include Tenten from Naruto's world. She might be interested in Naruto's adventures in a different universe and become part of the harem. In Starfire's world, there could be a scientist - type character who is fascinated by Naruto's ninja abilities and the concept of chakra. This character could start to develop feelings for Naruto as she studies him more closely, thus joining the harem.