There's a lot of surprisingly dark and scary anime out there. And it's not just the straight-up horror shows - sometimes, you don't realize the seemingly happy-go-lucky world of a series actually has horrifying implications. For example, you may not have noticed how existentially terrifying Free! is because you were too distracted by the fan service. Yu-Gi-Oh! can get so convoluted that it never occurred to you that the characters have descended into Hell halfway through the card game.
There are also some genuinely cheerful anime with super dark undertones. Gintama is mostly hilarious, but not so much once you get to the war part. Yuri!!! on Ice is a genuinely heartwarming show, if you glaze over the whole fat-shaming thing in the first few episodes. Fair warning: once you realize that your favorite series is a secretly depressing anime, you'll never look at it the same way again. Check out this list of anime and vote up the ones that are shockingly much more somber and dark than you remember.
Gintama is largely focused on parody and zany hijinks, so it's easy to forget that many of the characters have been through some serious sh*t. Yes, there's a cop who drinks mayonnaise like it's water, and yes, there's a giant duck named Elizabeth with nefarious goals and hairy human legs. But! There is also the main character, Gintoki, who has major PTSD from being an orphan child digging through corpses for food, being an adolescent fighting the Joei war, and from being forced to choose between killing his teacher and his friends.
Gintoki isn't the only character with a tragic backstory. The aforementioned mayonnaise guzzling policeman had a love interest who died of tuberculosis. Kagura, Gintoki's employee and informally adopted daughter, has a brother who wants to kill her because she was "weak" enough to beg him not to kill their dad. Oh, and at least five other characters are Joei war veterans.
Most nerdy pre-teens in the world have seen Naruto, but lots of people don't realize how truly disturbing this show is until they're much older. It's easy to get distracted by bad*ss action sequences, awesome magic, and silly fan service, but you could fill a book with all the things about the Naruto universe that are not just bleak, but downright horrifying.
For example, did you realize the world is populated by child soldiers? Nearly every single character has lost multiple loved ones to war and genocide. And what's with the weird, major theme of eyeball theft?
Fruits Basket is an allegedly cheerful shoujo anime about a girl named Tohru who forms a tight bond with the wealthy and mysterious Sohma family. The biggest mystery is that members of the family transform into animals when hugged by a member of the opposite sex. While the series does explore the ways in which the curse limits and isolates those it impacts, there are a lot of truly alarming things that the series glosses over.
For instance, social services doesn't appear to exist in this world. Akito, the family deity at the center of the curse, is an awful person. Whether it's whipping his cousin Yuki when they're both children, blinding his cousin Hatori (who is also his doctor) in a fit of rage because he dared to fall in love, or smacking a little girl across the room when he's an adult, Akito gets away with catastrophic physical harm. Somehow, no one outside of the family ever notices that anything is amiss.
Social services also falls down on the job when it comes to protecting minors from predators. Tohru's father was her mother's middle school teacher, Shigure and Ayame are 27-year-old men who are constantly making sexually inappropriate comments about 17-year-olds, and in the manga, Kyo's adoptive father ends up pursuing a relationship with his son's same-aged classmate, Hanajima. Because the series presents these things as either romantic or humorous, you might not have realized how messed up the first time - but if you take a closer look, the world of Fruits Basket is actually pretty nightmarish.
The whole Digimon franchise has some seriously messed up concepts in these seemingly cheerful kid shows. The basic premise involves placing massive amounts of pressure on young children. The Digi-Destined (or Chosen Children) are paired with Digimon partners with whom they're expected to save the world from destruction. While it's not unusual for shows geared toward kids to heap that kind of responsibility onto child characters, Digimon takes it to another level.
For example, in Season 1, Tai believes he is responsible for his sister's near death from pneumonia. Why? Because when he was inexplicably tasked with watching her when he was too young to look after himself, the illness she already had got worse. His mother blames him so hard that she actually hits him for it. That guilt follows Tai for years.In Digimon Tamers, a young girl named Jeri ends up so depressed from the death of both her mother and her Digimon partner that she begins to believe she deserves to die. She's manipulated by a being called the D-Reaper to believe that all of humanity needs to be eliminated, and suffers a complete mental breakdown.