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.
One popular one is 'The Rising of the Shield Hero'. It features a unique isekai setting where the protagonist is summoned to another world as the Shield Hero, and gradually forms a harem of diverse characters throughout his adventures.
One popular harem isekai light novel is 'In Another World with My Smartphone'. The protagonist is transported to a fantasy world with his smartphone and soon finds himself surrounded by various female characters. Another is 'Overlord', where the main character, Momonga, is trapped in a game world and has interactions with different female npcs that could be considered part of a harem - like situation. And 'The Rising of the Shield Hero' also has elements of harem isekai, with the main character, Naofumi, gradually gathering a group of female companions during his adventures in the isekai world.
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.
The escapism. People like to be transported to another world (isekai part) and experience a new and exciting adventure. The harem aspect adds a romantic and sometimes comical element. Having a group of characters of the opposite sex attracted to the protagonist makes for interesting relationship dynamics.
The appeal of harem isekai light novels lies in the escapism they offer. Readers can immerse themselves in a fantasy world where the protagonist often has a special power or ability. The harem aspect adds an element of romance and relationship building. For example, in 'In Another World with My Smartphone', the protagonist's ability to use his smartphone in a medieval - like world is cool, and his interactions with the female characters are fun to follow.
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.
They develop by having the protagonist gain power or status in the new world. This attracts female characters. In 'No Game No Life', Sora and Shiro enter a different world and their intelligence and unique abilities lead to them having a group of female followers. The plot also involves challenges and competitions that further the relationships in the harem.
One characteristic is the transportation to another world. This could be a medieval - like fantasy world, a post - apocalyptic world, or even a world based on different rules of magic or technology.
One popular one could be 'That Time I Got Reincarnated as a Slime'. It has elements of isekai and also develops a sort of harem-like situation around the main character Rimuru. Another might be 'Overlord', where the protagonist Momonga finds himself in a new world and has various female characters around him that could be seen in a harem - like context in a way.