For the past decade, isekai has been one of the most dominant genres in the anime industry, with every new batch of seasonal releases being filled with new shows for fans to engage with. While the genre and the various works that utilize it have received criticism over the years due to overexposure, questionable writing choices, and a perceived lack of originality, its popularity persists, and that’s likely only going to increase as the years go by.
While modern isekai has only recently reached mainstream success, there have been plenty of anime that hit many of the same themes and tropes the genre is known for. While these shows weren't known as isekai when they were originally released, their similarities make them something of a blueprint or "prototype" for what the genre would eventually become.
10 Inuyasha
One of the most popular examples of an anime that served as a blueprint for modern isekai is Inuyasha. Despite the anime and manga it was adapted from coming out well before the genre took off, Inuyasha's story follows, Kagome, a teenager who gets transported to Sengoku-era Japan to battle evil perfectly fits the most basic definition of an isekai: the protagonist being transported to another world.
Beyond that, of course, the series features all the classic comedy and action that Rumiko Takahashi is known for, and decades later, Inuyasha is still regarded as one of the best anime of all time.
9 Digimon Adventure
Another classic isekai from before the genre took off is Digimon Adventure. The anime's plot, which is centered on the protagonists being sent to the Digital World to fulfill their destiny makes it another series that falls into the classic definition of an isekai, and the series was a major success helped make Digimon a household name. Since then, nearly every Digimon anime has used some variation of the same plot, and while it's hardly the only contributing factor to Digimon's success, it's hard to imagine Digimon without this crucial element.
8 The Vision Of Escaflowne
Sunrise Studio is famous for mecha anime like Gundam and Code Geass, but one of their other hits from 1996 was The Vision of Escaflowne. With series protagonist Hitomi being sent to the mysterious planet Gaea, Escaflowne combined Sunrise's signature mecha battles with fantasy and romance, coming together surprisingly well. The Vision of Escaflowne is an incredibly unique anime that still more than holds up today, and even without the isekai angle, it’s certainly worth the praise that fans and critics alike have given it over the years.
7 Outbreak Company
Some of the best isekai anime are the series that subvert common tropes, and a great example of that is Outbreak Company. Outbreak Company differed from other isekai in that the characters willingly went into the story's fantasy world, doing so as part of a government mission to establish peace by teaching the fantasy world about otaku culture.
The series was a parody of the typical genre conventions of an isekai, and with how much the genre's grew in the decade since it aired, Outbreak Company's comedic stylings end up working even better in hindsight.
6 The Devil Is A Part-Timer!
Another form of isekai anime reverses the typical conventions of the genre to have the fantasy characters be transported to Earth, like the plot of the immensely popular The Devil Is a Part-Timer! The anime's comedy revolved around how invested in normal life the fantasy characters became, most notably with Maou's devotion to working at a fast food restaurant, and it quickly became a cult hit among anime fans.
5 The Familiar Of Zero
Regarding older isekai anime, one of the most notable of them all has to be The Familiar of Zero. The story of a young boy being summoned to a fantasy world by an inept mage and getting mixed up in comedic harem hijinks. The series was well-regarded by fans and critics, and eventually became the inspiration for some of the biggest modern isekai series.
The original light novel was so popular that many isekai authors, most notably Re:Zero's Tappei Nagatsuki, got started writing fanfiction of it on the web novel site Shōsetsuka ni Narō. It's safe to say that if it weren’t for The Familiar of Zero, modern isekai wouldn't be what it is today.
4 Sword Art Online
Perhaps the most Sword Art Online. With beautiful animation centered around a world where thousands of people become trapped inside an MMORPG, Sword Art Online was a tremendous hit that quickly spawned a massive franchise, and considering the timing of the anime's original release, its success likely helped pave the way for more and more isekai to get adapted into anime. Sword Art Online remains a very controversial series due to its polarizing characters and storytelling, but its impact on the isekai genre can't be understated.
3 Log Horizon
While having the same basic premise as Sword Art Online with people being trapped in a video game, Log Horizon had a bigger focus on game mechanics and the darker implications of its story, and with Sword Art Online season 1 having ended around the time Log Horizon premiered, the contrast made its strengths shine even brighter. Log Horizon is a more serious take on isekai anime, and with how controversial the writing in them often is, that's still plenty welcome a decade later.
2 .hack//SIGN
Another classic isekai anime, predating Sword Art Online's "trapped in a video game" storyline, is .hack//SIGN. While Tsukasa was the only one to be trapped in The World, the series still deconstructed a lot of future conventions of the genre such as escapism and antisocial behavior, making it a far darker take on isekai than the more traditional stories that would follow. One criticism of isekai anime is how being sent to another world is often superfluous to the story, so .hack//SIGN having a darker twist helps it stand out, even now.
1 Spirited Away
Perhaps a surprise for some anime fans, one of the most famous examples of a classic isekai is Studio Ghibli's Spirited Away. Spirited Away follows the most basic execution of the genre – the hero suddenly finding herself stuck in another world, and with the character writing, music, and visuals that are common of Studio Ghibli, it's easily one of the most stunning and well-crafted examples of an isekai. Modern isekai might be completely different from Spirited Away, but it still works as the absolute peak of what the genre is capable of.
Modern isekai has become oversaturated over the years, but that development was a very gradual process, and these older isekai anime and others are proof of that. Some of them did things that would eventually become staples of the genre, others went in directions that are still unique by current standards, but the one thing they have in common is showing how long the basic tenets and tropes of isekai. Isekai anime has long since taken on its own identity, but it's easy to see these older works and others as having helped bring that about.
