Well, 'The Rising of the Shield Hero' can be considered. The protagonist is summoned to another world, which is a typical isekai tensei situation. And he has a group of female companions who support him in different ways, which gives it some harem - like vibes. Also, 'Konosuba: God's Blessing on This Wonderful World!' is very popular. The main character is sent to a fantasy world (isekai) and he has a group of girls around him, which is a classic harem setup in light novels.
A few 'isekai tensei harem novel' titles are 'Sword Art Online'. In the ALO and other arcs, Kirito has interactions with multiple female characters that have some harem - like qualities. And 'Log Horizon' is also relevant. Shiroe, the main character, is in a world full of different races and characters, and he has relationships with several that can be seen in the context of a harem in the isekai setting.
There's also 'Sword Art Online' which, while not strictly a traditional 'isekai tensei no boukensha' in the purest sense, has elements of being transported to a different virtual world that can be considered in a similar vein. It's very well - known for its action - packed battles and interesting character relationships.
Some popular ones might include 'Isekai Onsen ni Tensei: My New Life as a Hot Spring Owner'. It's a common concept where the protagonist is reincarnated in an isekai world related to hot springs and has various adventures.
One popular 'isekai harem novel' is 'No Game No Life'. In this story, the two main characters are transported to a different world filled with games and rules. They encounter various female characters, and a harem - like dynamic develops as these characters are drawn to the protagonists' intelligence and unique abilities.
One popular title could be 'In Another World's Labyrinth, My Harem Awaits'.
There's no easy answer to whether it's popular. Popularity can vary depending on different factors. In the world of light novels, marketing also plays a big role. If the publisher has promoted it well, it might have reached a wider audience. Also, word - of - mouth is important. If early readers found it amazing and recommended it to others, it could have gained popularity. However, without more information on things like its availability in different regions, the number of translations, and its presence in popular bookstores or online platforms, it's hard to determine its overall popularity.
Well, for one thing, the isekai tensei concept allows for a fresh start in a completely new and often fantastical setting. This gives the author a lot of room to create unique worlds, magic systems, and species. The harem part is appealing because it offers different types of relationships and character dynamics. Different characters in the harem can have their own personalities, backstories, and growth arcs. For example, in some novels, one girl might be the strong and silent type, while another is the bubbly and energetic one. The protagonist then has to navigate these different relationships, which adds depth and variety to the story. Also, it can appeal to different reader fantasies about love, friendship, and adventure all rolled into one.
One popular 'isekai onsen light novel' could be 'Isekai Onsen ni Tensei Shita Ore no Kounou ga Tondemo Sugoi'. It combines the elements of isekai (another world) and onsen (hot springs). The story might involve the protagonist being transported to a different world where the onsen plays a significant role, perhaps having special powers or being a central location for various events.
Another well - known one might be 'Overlord'. In this light novel, the main character is transported to a new world while being in the form of his in - game avatar, an extremely powerful undead. It shows his adventures and how he rules over his new domain.
One popular 'isekai ojisan light novel' could be 'Isekai Ojisan: Isekai ni Tensei Shita Kedo Cheat Nanka Shinai yo'. It tells an interesting story about an uncle who gets isekai -ed but doesn't have the typical cheat skills.