The 2010s were dominated by isekai. The genre mainly revolves around a protagonist from the “real” world who finds themselves transported to an entirely new world, often a fantasy-based one. Despite its bizarre premise, it’s become one of the biggest sub-genres within anime. Lately, it’s impossible to go a season without seeing at least a handful of isekai series, and it's these shows that usually end up being the most popular.
However, as studios have been constantly pumping out isekai series to meet demand, many of them have turned out less than subpar - most being released at the end of the decade, after the proliferation of isekai. Fans have also become far more critical of the genre and have turned to sites like IMDb to make their criticisms and displeasure known.
Updated on September 29th, 2022 by Jeremy Lim: Even to this day, isekai continues to dominate the anime landscape, and IMDb remains a great site for anime fans to voice their opinions. As time has passed, anime fans have come to appreciate some of the anime on this list and look upon them in a more favorable light. On the other hand, some of these series have become even more reviled, ending up as some of the worst anime series of all time.
10 Arifureta: From Commonplace To World's Strongest
7.1
Developed by studio White Fox, Arifureta might’ve been the biggest disappointment of the Summer 2019 season. The story sees an entire high school class teleported to an alternate world. When the weakest of their members, Hajime, finds himself betrayed, he winds up at the bottom of a labyrinth none of the group is prepared for.
However, Hajime finds the resolve to return to the surface and leave the fantasy realm. With the light novel debuting in 2013 and still ongoing, the anime tried to rush through as much of the story in 13 episodes as possible, causing it to become hated, even among its already established fanbase.
9 Maou-Sama Retry
6.7
Akira Oono manages a VRMMORPG known as Infinity Game and often plays as the character known as Hakuto Kunai, the Dark Lord. Oono logs in one day and winds up being transported into the game. There, he has all his powers and is frequently challenged by people aiming to defeat him.
Saving a young girl named Aku at the beginning of his adventures, Oono decides to take her with him to help him understand this world. The most unique part of this series is its usage of an older male as a protagonist. Other than that, there is nothing remarkable about this series.
8 In Another World With My Smartphone
6.6
The relatively high rating is baffling to some fans as this series has nothing going for it. The main character, Touya, is transported to another world after being killed by a higher being. In this other realm, Touya has incredible magic, better speed, enhanced reflexes, and an improved memory.
Most importantly, he also gets to keep his smartphone, which is still somehow relevant even though he’s a top-tier spellcaster. There’s no overarching story, and Touya just spends his days flirting with girls far out of his league.
7 The Ones Within
6.4
Akatsuki Iride is a fan of video games and has become popular for his Let’s Play videos. Recently, Akatsuki cleared a game known as The Ones Within – Genome, and rumors say anyone who beats it will vanish.
Sure enough, Akatsuki finishes the game and gets transported to another world. In this new universe, he’s asked to finish a new game, working alongside people who’ve also been brought to this world to get the “chromosome” and reach 100 million viewers. While it has a unique enough premise, it ended on a cliffhanger, disappointing many fans.
6 High School Prodigies Have It Easy Even In Another World
6.2
Most isekai series pretend that their overpowered protagonists aren’t really overpowered. However, High School Prodigies doesn't bother to pretend. Right out the gate, they established these seven kids were overpowered in the real world.
So much so that after they were transported to a new world, these characters were able to take over and restructure everything from commerce to technology. Still, this series has a low rating because of how boring and predictable it is.
5 Isekai Cheat Magician
5.4
Taichi Nishimura and Rin Azuma were living normal high school lives until they got teleported to a different world by a magic circle. In that world, things are far more fantastical, containing everything from elves to beastmen.
Both Taichi and Rin want to become adventurers, but they find out their powers are vastly greater than some of the strongest mages in the land. Most isekai series eventually become power fantasies, but Isekai Cheat Magician straight-up makes it the core of the story.
4 The Master Of Ragnarok And Blesser Of Einherjar
5.3
When a high school teenager, Yuuto, decides to mess about with a myth involving a nearby shrine, he gets teleported to a different world. There, everything is based on clans doing battle with one another for dominance.
Yuuto is then dragged into the Wolf Clan and uses the superior knowledge he has from his solar-powered cellphone to bring the clan victory after victory. This could have been a decently cool action series, instead, it devolved into a run-of-the-mill harem, with Yuuto being surrounded by women everywhere he goes.
3 Do You Love Your Mom and Her Two-Hit Multi-Target Attacks?
5.2
Even though this series contains some of the best pouting reactions in anime, it’s wasn't really a hit among fans. The series follows Masato Oosuki and Mamako Oosuki, a mother and son duo who get transported to a game world together.
Masato is initially excited to show his skills until he learns that it’s actually his mother that is absurdly powerful. The world is designed to help strengthen the bond between parent and child, but the series just comes off as creepy, even if the mother is one of the most likable anime characters of 2019.
2 Seven Senses Of The Re'Union
4.8
This story is set in a world of a popular VRMMORPG Union that has a top clan, Subaru, completely consisting of elementary school kids. One day, one of the kids dies in the game. This death leads to the game being shut down. However, several years later, the game is revived as Re-Union.
The members of Subaru are pulled into the game when they learn that their dead friend somehow seems to be inhabiting the world of the game. Many fans were put off by how much the anime series seemed to pull from Anohana: The Flower We Saw That Day and Sword Art Online.
1 Conception
3.9
With a contrived plot that is little more than an excuse for harem shenanigans, Conception is widely considered to be one of the worst anime of all time. Itsuki, a high school graduate, gets summoned to another world, Gravania, that is in chaos because of the Impurities.
Itsuki is told only he can fix everything by meeting and producing "Star Children" with each of the Star Maidens, as only his children can fight off the Impurities. Until he’s able to do so, he isn’t allowed to go back home. Fortunately, Conception lasted only one season.