The Isekai genre is one of the most popular among anime fans. Consisting of characters from our world being transported to a fantastical, supernatural, or otherworldly universe, the isekai genre has a magical charm that makes it appealing to many audiences. Paired with incredible art styles, animation, and storytelling it's not difficult to see why this genre is so vastly popular.
Isekai characters are therefore also popular within the anime community. Say "Rem" and everyone knows exactly who's being discussed. The protagonists within this genre are made to be relatable and easy to root for, while the rest of the characters shine with their unique personalities and often magical abilities. Even the villains, love them or hate them, are usually well-written and memorable in their own right. Some of these well-adored characters, however, are vastly different in the manga and light novels from which they come. In contrast, others were never even in the source material.
This list includes spoilers for Re:Zero - Starting Life in Another World and Inuyasha.
6 Rem (Re: Zero - Starting Life In Another World)
Rem is quite possibly the most popular character to emerge from Re:Zero. Fans of the show are familiar with her sweet and lovable personality. While she starts off as a somewhat suspicious and untrusting character in the second arc of the show, she quickly becomes one of the best characters as she starts to trust Subaru and audiences learn more about her. The way she cares deeply for those around her as well as her incredible loyalty makes her personality shine.
The scene where Rem confesses her love for Subaru is easily one of the most emotional moments in the anime. In this scene, Rem pours her heart out to Subaru, expecting nothing in return from him and accepting when he says that he loves Emilia. In the light novel, however, Rem shows a manipulative side to herself when she pretends she is dying in Subaru's arms to get him to confess his feeling for her. This scene happens shortly after they defeat the white whale, and Subaru does confess, only to find out Rem was playing around.
5 Naofumi Iwatani (The Rising Of The Shield Hero)
After being summoned to a fаntasy world, in typical isekai fashion, Naofumi quickly finds himself in a world of trouble. As the "weakest" among the four heroes in The Rising of the Shield Hero, the people of the world look down on the protagonist. Within a day of his new life, Naofumi is betrayed by his teammate, Myne, and is falsely accused of a crime he did not commit. Society shuns him, his reputation is ruined, and he has no way home until the waves of monsters which threaten this kingdom have been defeated. Naofumi becomes a shell of his former self, becoming a cold and mean individual.
Due to the heavy themes this show deals with, it has been met with some backlash and controversy in its time. Especially with Naofumi's mean character after he is falsely accused. As far as isekai anime goes, this one is quite dark and serious, with its light novel counterpart being much darker than the show. In fact, in the light novels, Naofumi becomes much meaner, he is misogynistic and brutal and even tells his companion Raphtalia that he would enjoy watching her die, so he can pretend it's Myne. Of course, in the light novels, this behavior was more justifiable as readers could see his internal thought process and realize it was all coming from a place of being deeply wounded. In contrast, the anime had to tone his behavior down due to the nature of the format.
4 Albedo (Overlord)
Albedo is an important and central character in Overlord, she is a fan favorite as well as one of the first characters introduced in the anime. She plays an important role as the overseer of the floor guardians and is known for being infatuated with the protagonist, Ainz. Albedo is loyal, proud, and dedicated, and it is difficult to imagine Overlord without her.
While Albedo is a prominent character in the anime and the light novels, it may come as a surprise that she was not in the original web novel at all. Instead, her role as the overseer of the floor guardians was given to Demiurge in the web series. Naturally, her sisters were also not in the web novel. According to the creator, Maruyama, she was added to the light novel so that Ainz would be able to move freely outside the Great Tomb of Nazarick.
3 Dust And Keith (KonoSuba: God's Blessing On This Wonderful World!)
Dust and Kieth are two adventurers in a team of four in KonoSuba. In the anime, they are introduced while they're lurking near a succubus bar, and Kazuma briefly mentions that he's gotten to know them recently. All in all their interaction is brief, and they are barely in the episode at all. In contrast, their introduction in the light novel is much more interesting.
In the light novel, Kazuma encounters Dust and Keith after their party berates him for being dead weight to his own team, which they refer to as a "harem". Kazuma agrees to swap teams with Dust for the day in order to prove them wrong. In the end, Kazuma ends up being quite useful to the other team, using his quick thinking and logic skills to get them out of various situations. When they return to the guild, Dust is in tears due to dealing with Aqua, Darkness, and Megumin all day, and he even apologizes to Kazuma.
2 Kagome Higurashi (Inuyasha)
Inuyasha is an instant classic when it comes to isekai anime. It follows the story of Kagome Higurashi when she transports 500 years into the past to feudal Japan. It is a charming shonen-type anime with comedy, romance, and gripping action. It is also renowned as one of the first series to deal with Japanese folklore and mythology, and it does so through the eyes of Kagome, the daughter in a family of shrine keepers.
There are many differences between the manga and the anime. Because of the format, the anime is able to bring more comedy and a larger focus on romance to the series. For example, the romance between Inuyasha and Kagome is more prominent, and they kiss in the anime whereas this doesn't happen in the manga. This emphasis on romance in the anime also means that Kagome is less understanding of the relationship between Inuyasha and Kikyo than she tends to be in the manga.
1 Tanya Degurechaff (Saga Of Tanya The Evil)
Saga of Tanya the Evil combines the magic of the isekai genre with the serious themes surrounding war. The main protagonist is Tanya, a Japanese salaryman who has been reincarnated as a female child soldier. It is based on an alternate reality of World War 1, where magic is involved in the fighting. This anime is known for being quite different from the light novel. This is due to it having 12 episodes, which oftentimes meant that some of the details of the story had to be sped through, resulting in something quite different from the info-packed original light novel.
The protagonist herself is quite different too. In the light novel, Tanya appears quite reasonable and analytical. This is likely due to the novel's own strategy-based and logical nature. In the anime, Tanya appears as a more antagonistic character, with less regard to feelings than her light novel counterpart. After all, there is only so much detail that can go into a 12-episode anime. The medium of the light novel naturally allows the writers to go into more depth with Tanya, which could be the cause of these differences in her personality.