In the world of Kemono Jihen, supernatural creatures like kitsune and tanuki live in disguise within human society. Most of those creatures simply wish to coexist with humans, but some of them will misbehave and start to mess around and even hurt innocent people. When such a thing happens, a Kemono detective agency will be called upon to solve the problem. Inugami the tanuki, the head of the detective agency, along with the kemono children that he took under his wing will solve every mystery and conflict that happens between humans and kemono.

Kemono Jihen combines elements of action and mystery into one exciting series. Every new case that they encounter, which can be either amusing or terrifying, takes us deeper into the complex world of kemono and that is the reason why it deserves a spot in this list.

Ai Ohto is a girl who becomes a hikikomori following the suicide of her friend, Koito Nagase. One night during her late-night stroll, a mysterious voice guides Ai to an abandoned gacha machine where she receives her first wonder egg. Cracking the egg transports Ai to a dream world where she has to protect a girl who comes from the egg from a horde of evil monsters. The mysterious voice also tells Ai that if she can save enough people, her dear friend Nagase can be revived. So Ai decides to purchase more wonder eggs and fight in the dream world every night.

Despite the colorful monsters and over-the-top fighting scenes, the foundation of Wonder Egg is a carefully-constructed psychological thriller. The themes of guilt, regrets, and lack of self-esteem are the main driving force for every character. However, rather than going through the usual slice-of-life drama, Wonder Egg uses action and fantasy to develop the characters and resolve the mystery and that is what makes this anime stand out from the rest in the genre.

In the world of The Case Study of Vanitas, a vampire’s true name is the key to his existence. Unfortunately, a blue-eyed vampire named Vanitas created a book called “The Book of Vanitas” that can find out and manipulate a vampire’s true name.

Fast forward a couple of centuries to the beginning of the series, a human who uses the name “Vanitas” appears out of nowhere and he possesses the genuine Book of Vanitas. However, instead of killing the vampires, Vanitas uses the power of the book to save them from a disease called Malnomen that can corrupt their true name while he investigates the perpetrator behind the recent outbreak of this malicious disease.

The Case Study of Vanitas is an adaptation of the manga by Jun Mochizuki, the creator of Pandora Hearts, so you can expect lots of interesting characters, amazing worldbuilding, and more importantly, a carefully-woven mystery both on the small and individual level to catastrophic events that can threaten the whole world.

Pretty Boy Detective Club may seem like a tacky title for a mystery anime, which is why not many people had seen this anime during its initial run. However, the fact that it is based on a novel by Nishio Ishin, the creator of Monogatari Series, and created by none other than studio Shaft, is why you'll undoubtedly feel intrigued and curious about this series.

This anime is as over-the-top and as interesting as every other Nishio Ishin's works. Pretty Boy Detective is about a secret detective club consisting of five pretty boys who only take what they consider to be beautiful cases. From deducing the truth behind a counterfeit bill that looks better than a real bill to searching for a missing star in the sky, these pretty boys can solve it all. The combination of absurd cases and eccentric characters are what will ultimately keep your eyes glued to the screen.

Moriarty The Patriot is a story where James Moriarty and his brothers are the anti-hero who tries to change the world for the better while Sherlock Holmes is the one who always stands in their way. The first season established James Moriarty as someone who won’t hesitate to commit crimes in the name of justice and greater good.

This second season of Moriarty The Patriot starts with Irene Adler, a thief and former actress who unknowingly steals documents containing the sinister secrets of the British Empire. Fear for her life, she uses the help of both Sherlock Holmes and Moriarty brothers to disappear from the clutches of the Empire. Thus begins the web of lies, betrayals, crimes, and mysteries that can affect the fate of the entire nation.

Moriarty The Patriot is a series that is always tiptoeing between the concept of good and evil and between the small individual events and the grand conspiracy. This second season further solidifies that concept to the point that we the viewers can't even guess what the characters will do and what will happen next.

Lupin III is the third generation of thieves who use the moniker of “Lupin”. He travels around the world to steal precious gems and priceless items with the help of his quirky colleagues. Every Lupin III series has always worked in two different levels. There are small cases that pop up every several episodes and there's the overarching mystery that takes the entire series to conclude. The sixth iteration of this legendary series is no different.

In this series, Lupin and his colleagues go after the first train ticket in Britain, the missing original short story by Hemingway, and lots of other little adventures, all the while he is on the run from Sherlock Holmes for the supposed crime of killing John Watson. Not only that, there’s also a mysterious organization that somehow has connection to everything that happens since the first episode. You really won't run out of excitement and mysteries with this current chapter of Lupin III’s adventure.

Beastars is a coming-of-age story of Legosi, a shy gray wolf who is a member of the Cherryton Academy drama club. The first season saw Legosi become one of the stars of the drama club alongside his senpai named Louis, a rich and proud red deer. However, there was still a gruesome murder of Tem, a friend of Legosi from the drama club, that has yet to be solved.

This second season of Beastars picks up right after the events in the first season. Legosi decides to take on the role of the detective and begins to look for the carnivore who killed his friend. Meanwhile, Louis becomes the leader of a pack of yakuza lions and forces a slab of meat down his throat to assert his dominance.

This second season takes everything great about the first one and turns it all up to eleven. The characters receive further development, the romance is more pronounced, the dynamic relationship between carnivore and herbivore is getting more intense, and naturally, the mystery is also more captivating than ever.

If another series takes its time to set the foundation of the story, Sonny Boy chooses to go a different route and throw viewers into the mystery right from the very first frame. When we meet the main character, Nagara, his school along with several other students has been transported into a foreign world. To make matters worse, some of the high schoolers awaken super powers that threaten the stability of what is already a very precarious situation.

This premise of classmates transported into another world is nothing new. However, what makes Sonny Boy different is its ability to add such deep sci-fi elements to the story along with so many metaphysical and confusing concepts. The inclusion of those elements adds another layer of complexity to the already interesting mystery.

Imagine a massive castle where the occupants are a family covered in such a thick black soot from head to toe that it is impossible to even see their facial expressions. In order to better communicate with each other, the leader of the family creates human-like living dolls that will become their face. When not in use, the dolls serve as maids to their respective shadow masters.

The concept behind Shadows House is both bizarre and intriguing at the same time. The story is presented in a cute and creepy manner while everything else is covered in a thick veil of mystery. There’s the sudden appearance of a phantom soot, the true meaning behind the shadow ritual, the real origin of the living dolls, and so many other mysterious events that happen within the Shadow House. That's why if we're talking about an anime that is shrouded in mystery, then Shadows House is definitely one of the top contenders.

Odd Taxi follows a 41-year-old walrus taxi driver named Odokawa and other anthropomorphic animals as they go through their mundane everyday life. However, in the middle of his tedious job, Odokawa encounters a web of seemingly unrelated events that keeps getting more complicated by the minute. A teenager who wishes to go viral, a fractured idol group, an estranged comedic duo, a low-level mafia, a corrupt cop, a missing high school girl, a man who's obsessed with online gaming, and the list goes on and on.

Each episode of Odd Taxi adds new complications to the mix while raising the stakes at the same time.It is actually impossible to guess what will happen in each episode which is what makes this series so gripping and interesting.

You will find yourself beaming with curiosity and anticipation for every new episode while feeling confused and clueless at the same time. Odd taxi is the only series in this list that can do that to you and that is the reason why it deserves the crown of the best mystery anime in 2021.