The Spring Season of anime for 2021 was full of quite a lot of incredible new shows and continuing series. From My Hero Academia’s 5th season to the massively underrated Odd Taxi, there were plenty of amazing shows to watch week by week, some of them even continuing into the Summer season as well.

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And, while Summer 2021’s season isn’t quite packed as tightly, there are still a few standout series that people may be unknowingly missing out on. So, from least to most underrated, here are our picks.

10 Battle Game In 5 Seconds

Battle Game In 5 Seconds - Main Character Akira Holding His Cannon Arm Toward The Camera
  • Animation Studio: SynergySP
  • Where To Watch: Crunchyroll, VRV
  • Genre: Supernatural, Fantasy, Isekai (sort-of), Violence, Mystery, Thriller

First up is a long-awaited manga adaptation of another "trapped in a deadly battle royale" setting. While it involves the main character being "transported" to somewhere fantastical, it's still the real world so it technically doesn't count as "isekai". Battle Game In 5 Seconds has much more in common with shows like Gantz, Btoom, Darwin’s Game, or Deadman Wonderland than it does with the more “fantastical” type of isekai anyway.

This series features a cast of characters transported to another “world” with captors that give them oddly specific superpowers and put them in various situations that force them to use these abilities to the utmost. Battle Game In 5 Seconds has violence, a unique main character, inventive abilities, and much more.

9 How A Realist Hero Rebuilt The Kingdom

How A Realist Hero Rebuilt The Kingdom - Souma Sitting On His Throne With Liscia Next To Him
  • Animation Studio: J.C Staff
  • Where To Watch: Funimation, Hulu
  • Genre: Action, Fantasy, Romance, Isekai, Supernatural

One of the only “big” gripes about How A Realist Hero Rebuilt The Kingdom is the fact that the studio (J.C. Staff) decided to completely rework the original art style of the manga it was adapted from. Sometimes the anime adaptations improve upon the original work, but this sort of feels like the opposite. Other than that, this series is a perfectly serviceable (and relatively unique) take on the oversaturated isekai genre that is much more in line with Log Horizon than it is something like Sword Art Online.

Souma, as per usual for the genre, is an intelligent and well-meaning MC who is summoned to an isekai world to be their hero. Yet somehow, right after arriving, the king of the nation who summoned Souma decides to abdicate his crown to the protagonist! From there, this anime has all the stereotypical concepts. But, it’s all viewed through the lens of a guy (with a surprisingly sad backstory) trying to use his political and socioeconomic know-how from the modern world to save this kingdom that was thrust upon him.

8 The Dungeon Of Black Company

The Dungeon Of Black Company - Cover Art With Kinji Smiling At The Camera With Coins In His Hand And Rimu Hanging On To Him
  • Animation Studio: Silver Link
  • Where To Watch: Funimation
  • Genre: Isekai, Fantasy, Comedy, Action

Compared to How A Realist Hero Rebuilt The Kingdom, The Dungeon Of Black Company isn’t quite as “good”, but it’s a lot better than it might appear at first. While Souma focuses on making money honestly and efficiently for the good of the Kingdom, Nonomiya will use anything and anyone to greedily make cash and claw his way back towards the "Ultimate NEET" lifestyle he had so proudly accomplished before being whisked away to an isekai world. Frankly, he's a villain in his own way.

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The two shows are in the same genre, but they couldn’t be more different in style, tone, and sense of humor. But, because of that, people can watch both of these anime without getting too burnt out on isekai for the year (probably).

7 Kageki Shoujo AKA "Opera Girl"

Kageki Shoujo - The Banner Art For The Anime With All Of The Main Cast Posing Together
  • Animation Studio: Pine Jam
  • Where To Watch: Funimation
  • Genre: Shoujo, Drama, School Life, Slice-Of-Life

Finally, it is time to dive into some of the more adorable anime of the Summer Season, starting with Kageki Shoujo, the show with two of the most memorable female protagonists of recent seasons. But, Sarasa (the secondary lead) isn’t a typical “shoujo” character, she’s incredibly tall and a big ball of chaotic energy, making her a perfect complementary contrast to the calm and collected Ai Narata (the actual lead).

This series takes place at a fictional prestigious Japanese Opera Academy, and it uses that setting to say a lot about Japan’s Entertainment industry, the pressure of performing, and many more surprisingly adult topics.

6 The Aquatope On White Sand

The Aquatope On White Sand - All Of The Main Cast Standing Together For The Cover Art In Front Of A Big Bubble Full Of Fish
  • Animation Studio: P.A. Works
  • Where To Watch: Crunchyroll, VRV
  • Genre: Slice-Of-Life, Fantasy, Drama

Anyone familiar with P.A Works instantly added The Aquatope On White Sand to their watchlist as soon as they saw they were the ones making this series. This animation studio excels at beautiful compositions, meshing fantastical elements with very “realistic” characters/situations, and visual spectacle in general.

Aquatope mainly revolves around two characters, Fuuka Miyazawa (a failed idol who ran away to Okinawa) and Kukuru Misakino (the granddaughter of an aquarium owner), as they try and figure out how to keep the Gama Gama Aquarium from closing down. And, if that sounds like a unique concept, it really is, and it makes for a very relaxing yet interesting watch.

5 Tsukimichi Moonlit Fantasy

Tsukimichi Moonlit Fantasy - Tomoe Messing With Makoto
  • Animation Studio: C2C
  • Where To Watch: Crunchyroll, VRV
  • Genre: Isekai, Comedy, Action, Fantasy, Supernatural

This is the last isekai series to make the cut, thankfully. While anime has been completely oversaturated with this genre in the past couple of years, there are some standout examples now and then.

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Protagonist Makoto Misumi's back and forth with his "servants" Mio (a cataclysmically powerful spider monster) and Tomoe (a greater Dragon obsessed with Japanese history) are hilarious, and the character takes the “overpowered isekai MC” trope to new heights. To be more precise, Tsukimichi Moonlit Fantasy is a show about a character who is "supposed" to be an underdog quickly becoming someone able to take on the gods themselves.

4 Remake Our Life

The Main Cast Of Remake Our Life All Walking Together
  • Animation Studio: Studio Feel.
  • Where To Watch: Crunchyroll, VRV
  • Genre: Slice-Of-Life, Drama, Fantasy, Romance

The wish-fulfillment trope that makes isekai-type shows so popular and the tropes about characters getting to have a “second chance at life” usually go hand-in-hand. Well, unsurprisingly, Remake Our Life is one of those stories, but it's a realistic anime, rather than one focused on magic and monster-slaying.

As one would expect, this show is incredibly comfy, heartwarming, and uplifting to watch; in fact, it’s just well-made in general. So, for anyone who has ever had an interest in the fine arts, art schools, game design, or any kind of “craft”, this might be the perfect show for them.

3 The Idaten Deities Know Only Peace

The Idaten Deities Know Only Peace - Cover Art With All Of The Main Cast Visible As The Fly Towards The Background
  • Animation Studio: Mappa
  • Where To Watch: Crunchyroll, VRV
  • Genre: Action, Adventure, Seinen, Fantasy, Violence

Moving on to a controversial inclusion, it’s The Idaten Deities Know Only Peace, made by Mappa studios. Now, this series is one of the rare ones on Crunchyroll to get a “mature” rating and a warning before each episode, and that’s primarily from a certain horribly untasteful scene in the first episode.

And, while these misguided "jokes" do pop up again from time to time, the rest of the anime showcases a unique new concept animated by a fantastic studio that also has quite a memorable art style. Granted, it won’t be everyone’s cup of tea, and the story's writing isn’t the best, but this is the perfect “popcorn” show just to watch cool fights happen.

2 Sonny Boy

Sonny Boy - Nagara Looking At The Camera With All Of His Classmates Behind Him
  • Animation Studio: Madhouse
  • Where To Watch: Hulu, Funimation
  • Genre: Psychological, Supernatural, Fantasy, Sci-Fi, Mystery

The only reason Sonny Boy isn’t first is that it’s, admittedly, an incredibly weird show. It’s also incredibly good, but this anime is the type of oddity that doesn’t exactly appeal to the widest demographic. That said, for those who are fans of Madhouse’s past works or the past directorial/writing work of Shingo Natsume (AKA Space Dandy and One-Punch Man), Sonny Boy should be right up their alley.

It has weird superpowers, larger-than-life characters with obviously deep flaws, one of the most interesting settings seen in years, and a lot of great dialog moments. This show is easily a shoo-in for top anime this Summer Season, but that'll differ from person to person.

1 The Case Study of Vanitas

The Case Study Of Vanitas - All Of The Main Cast Together And Posing
  • Animation Studio: Bones
  • Where To Watch: Funimation, Hulu
  • Genre: Supernatural, Vampires, History, Fantasy, Action, Mystery

Onto the final inclusion on this list, The Case Study Of Vanitas. Now, as far as production and source material goes, this show is anything but underrated considering it’s animated by Studio Bones (AKA the studio behind mainstream Shonen series like Fullmetal Alchemist and My Hero Academia). But, more than that, it’s also written by Jun Mochizuki, the renowned mangaka behind Pandora Hearts.

Yet, despite all that hype, the show doesn't seem to have that many people talking about it on social media. Every vampire is as memorable as some of the best characters from Castlevania, the mystery is engaging, the setting is awe-inspiring, and the dialog is so over the top in the best way.

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