The isekai subgenre in Japanese anime has many familiar conventions and themes, most of all the sheer escapism factor that helps drive this subgenre's success. All works of fiction are escapism to some degree, helping viewers lose themselves with new characters and worlds, but isekai takes it to an extreme, usually at the cost of their protagonists.
Isekai protagonists are mocked for all their cliches and tired tropes, such as getting a harem or being too overpowered, but the worst problem is personal and has little to do with harems or OP magic. Too many isekai protagonists are defined entirely by their escapism, acting like aimless tour guides in a fictional world, and they truly leave behind their original lives in every way that counts. Fortunately, the best isekai protagonists do the opposite, and isekai needs more characters like that.
The Worst Isekai Protagonists Are Hollow Escapism Fantasies
No matter how well or how badly written they are, isekai anime protagonists tend to share the same basic storytelling elements inherent to isekai itself. These protagonists are often written to be stand-ins for the viewers, who may be bored with or frustrated by the tedious grind of everyday life at school or at the office. Deep down, many anime fans wish they could leave it all behind and wander freely in a new world, and that drives the appeal of isekai — and post-apocalyptic stories, too, for that matter. It's a fantasy about breaking free of today's stifling and too-familiar world, and that's a fair basis for writing an isekai protagonist. The problem is when that's all the protagonist is doing.
The worst-written isekai protagonists, such as Yuji in My Isekai Life or Kelvin the summoner in Black Summoner, are shallow in their design and are merely tools for escapism and power fantasies, and little more. Outwardly, characters like Yuji and Kelvin are dull and uncompelling because they're overpowered and can defeat any foe they face, but external power trips aren't even the worst problem. OP isekai characters can be fun, as Rimuru Tempest and Ainz Ooal Gown show, but if these characters have nothing on the inside, they're doomed to be a hollow excuse for escapism fantasy. Such characters are a tool for the narrative and not a fleshed-out character who operates like a real person.
These characters can drive the story forward by exploring a fantasy kingdom or meeting new people, and they can certainly fight high-voltage battles to save the day or defeat the obligatory demon king villain. However, if a character like Yuji or Kelvin is just an excuse for escapism fun, and they're not a true character, then the anime is focusing too much on the wrong thing, and the narrative falls apart. Characters like these have no potential for personal growth, introspection, or sympathy since they're a cheap narrative tool that was never even written to be a well-rounded person. Such characters can change their social lives and professional standing for the better, such as recruiting new adventurer friends to their side or rising in the ranks at an adventurer's guild. But it's no substitute for having a clearly-defined personality with personal quirks, flaws, goals, dreams, and fears.
In this way, narrative tool characters like Yuji and Kelvin are making a statement in isekai but not making a point, so their resonance as escapism fantasies runs dry too soon. Like any isekai character, they start off strong as an escapism fantasy who's ready for adventure in a new realm, something many anime fans wish for deep down. These characters' external lives are reinvented, such as going from a lonely NEET or salaryman to a sword-slinging hero fighting goblins, but if their personal arc lags behind, then it's all for nothing. These characters make a statement about how fans wish to escape the stifling real world, then fail to make any particular point about it.
Would a reincarnated person secretly regret leaving their old life behind, and what does that say about them? What will the protagonist's actions in this sandbox-mode world say about their true nature, for good or ill? Isekai reincarnation allows the protagonist to show their true self that was hidden or repressed in their original life, and an anime could do practically anything with that premise. Too often, these characters become generic adventurers with bland personalities and no particular goals, all because they're self-inserts who only represent the viewer's desire for escapism and adventure at the cost of never actually being someone on their own. But there are exceptions.
The Most Sympathetic Isekai Heroes Do Something With Their Escapism Fantasies
The best isekai protagonists are those who stand for something and express their true selves with their reincarnated lives. Whether or not these characters are externally overpowered, and no matter what shape or form they have, it's what's on the inside that counts. Anime fans need a well-defined protagonist to latch onto and emotionally support, not just a generic tour guide. The best isekai characters use their own personalities, goals, and interests to express themselves rather than be a hollow excuse for escapism. These characters have the same starting point as empty characters like Yuji and Kelvin, but the difference is these compelling isekai protagonists act based on who they are, not what they are. And they have well-written, clearly-defined personalities to make them more exciting, dynamic, and sympathetic as actual people in another world.
This makes even the most outlandish isekai worlds and premises more engaging since there's a fully fleshed-out person holding it all together. One example is Rimuru Tempest, the hero from That Time I Got Reincarnated as a Slime. He did far more than throw around his powers and fulfill viewers' secret desires for escapism or harems. This reborn salaryman finally had the chance to express and act upon his highly altruistic and idealistic side, something he couldn't have easily done in 21st-century Japan.
Rimuru Tempest acted upon his kindness and tolerance to unite all monsters into a single nation, using his formidable skills to defend that nation and impress some characters into joining. His personality and noble goals are what drove the story most of all, giving Tensura a very human heart, with isekai and magic merely being the vehicles for Rimuru's great character design. When fantasy is the context for a great character rather than an excuse for a powerful lead, an unforgettable, thought-provoking adventure like Rimuru's is sure to follow.