For me, 'That Time I Got Reincarnated as a Slime' stands out. The world-building and plot development are really engaging. Also, the characters have a lot of depth.
Well, 'That Time I Got Reincarnated as a Slime' can be considered among the best isekai harem light novels. Rimuru, the main character, as he grows in power, attracts a diverse group of female characters. It has a great mix of action, world - building, and the harem elements are subtly done. Then there's 'No Game No Life'. The siblings in this novel are transported to a world where everything is decided by games. There are several female characters that are attracted to the male protagonist, Sora. The unique concept of the world and the strategic battles make it an exciting read. Also, 'High School DxD' is quite famous. It has a more traditional harem setup with the main character, Issei, constantly surrounded by beautiful girls. The story has a good blend of ecchi elements, action, and supernatural aspects.
If you're new to isekai harem light novels, start with 'No Game No Life'. It has an interesting concept and the harem aspect is more about the relationships based on the game - playing. 'High School DxD' is also a popular choice, but it has some more mature themes, so be aware. However, the story is exciting and the harem is a big part of the plot.
It's hard to say for sure if it's popular. There are so many manga and novels out there, especially in the isekai genre. If it hasn't been widely translated or promoted, it might not be very well - known to a large audience. It could be a niche work that only certain fans of the isekai and harem sub - genres are aware of.
Well, without having read it specifically, it could be that the 'isekai meikyuu de harem o manga novel' is centered around a male protagonist who is transported to a maze in a different world. In this maze, he encounters various female characters, which form a harem around him. The story could then follow his adventures in this strange new world, trying to survive the maze while also dealing with the complex relationships within the harem. It could also involve elements of fantasy, such as magic or special abilities that the protagonist and the harem members possess.
The harem aspect means there are multiple female characters who are attracted to the MC. In these manga, the relationships can range from simple admiration to deeper emotional bonds. The female characters often have diverse personalities and abilities, adding to the complexity of the story. For instance, in 'Death March to the Parallel World Rhapsody', the harem members include a princess, an elf, etc.
There's also 'Death March to the Parallel World Rhapsody'. The MC Ichirou Suzuki is overpowered and gradually builds up a harem of various characters in the isekai setting. The story has a mix of adventure, comedy and some harem elements.
Well, it's a bit hard to pinpoint exactly which was the very first one. But some early examples could include 'El-Hazard: The Magnificent World', which had elements of the isekai genre.
Well, 'Konosuba: God's Blessing on this Wonderful World!' is a must - mention. Kazuma is reincarnated in a fantasy world and teams up with a group of misfits, including some female characters who form a sort of harem around him. It's known for its humor and unique take on the isekai genre with harem elements.
Isekai Quartet indeed has a manga. It offers a different perspective and sometimes delves deeper into the story compared to the anime. The manga can be a great companion to the animated version for fans wanting more of the Isekai Quartet world.