Shonen anime has a broad appeal and a wide range of the genre is considered by audiences to house some of the most renowned in the entire medium. A lot of titles are not only popular for the massive action sequences that fans have come to expect but also their deep stories.
Another thing the shonen genre is jam packed full of is plot twists. Plot twists rely heavily on not only being big shock factor moments but also the time leading up to them. They are important to the story telling as well as being moments that stick in a viewer's mind. It is also important that when plot twists are used, they have a lasting impact on the story as a whole.
10 The Identity Of The Armored And Colossal Titans (Attack On Titan)
One of the things viewers have come to expect from Attack On Titan is its shocking moments. Throughout the series, there has been many huge plot twists that have left fans excited, shocked, and betrayed along with the main characters.
At the heart of Attack On Titan is the survey corps, so viewers were not expecting such a big betrayal from within. This is why finding out that Reiner and Bertholdt, two characters others looked up to, were the Armored and Colossal Titans was such a massive blow for characters and fans alike.
9 What Happened To Mikaela (Seraph Of The End)
In the first episode of Seraph Of The End, viewers are introduced to the apocalyptic state of the world where humans are few and vampires are the ruling race. Two of the surviving humans are orphans who dream that one day they will be free. This comes crashing down when in the first episode, it appears that Mikaela is killed by a vampire who he lets drink his blood to protect his friends.
In episode four, it's revealed that Mikaela was never killed but in fact turned into a vampire himself. This is particularly shocking after learning that Yuuichirou is a member of the Japanese Imperial Demon Army's Demon Moon Squad to avenge his friend's' death.
8 L's Death (Death Note)
Death Note is renowned for being one of the best anime in the genre. When L was introduced very early on into the series, he quickly became a favorite among viewers.
L's ultimate death at the end of the first major story arc was a complete shock to viewers. Not only because he was such a beloved character, but because the series made it seem like it would revolve around the cat and mouse of L and Light. Losing L so early on was definitely a massive shock to fans.
7 Koro-Sensei Didn't Actually Blow Up The Moon (Assassination Classroom)
When viewers are introduced to Class 3-E in Assassination Classroom, they quickly learn that their main goal is to kill their octopus-like teacher, Koro-Sensei. All of the students are competing to kill Koro-Sensei in a ploy to stop him from blowing up the Earth like he did the moon. But Koro-Sensei isn't allowed to bring harm to any of the class. In the end, it is revealed that Koro-Sensei wasn't actually responsible for the destruction of the moon in an incredibly sad twist that leaves viewers and students heartbroken.
6 The Reason For Itachi's Betrayal (Naruto)
Itachi was a character that was born into destruction and war. The horrors of seeing so much death from a young age turned Itachi into a pacifist at heart. However, viewers are shown that Itachi was the reason that his whole clan was slaughtered.
Later on, the truth behind Itachi's betrayal is revealed to fans. Danzo uses Itachi's childhood trauma of all of that war to manipulate him into killing his clan. He convinced Itachi that the coup his clan were planning couldn't be stopped without Itachi killing them all. All Itachi really wanted to do was protect his younger brother's life.
5 Nina Tucker's Fate (Fullmetal Alchemist)
Nina Tucker is a character that Fullmetal Alchemist fans are still talking about. She was introduced early on when the Elric brothers get pointed to her father, Shou, by Mustang in hopes of finding clues to get their bodies back. The family seem innocent enough and the brothers quickly become attached to Nina.
However, it is later revealed that Shou's alchemy practices are not innocent at all. As his yearly alchemy license exam nears, Shou panics and uses Nina along with her dog, Alexander, to transmute them into a talking chimera.
4 The Truth Of Grace Field House (The Promised Neverland)
Viewers going into The Promised Neverland blind had a massive shock coming their way from the first episode. In episode one, viewers are introduced to Grace Field House, an orphanage housing many children and their caretaker, Isabella.
Learning the truth of Grace Field House was really where the horrors of the anime began. Where viewers and characters alike are happy to see one of the children being adopted, that soon ends when it turns out the children are being raised as food for the demons who rule the world and Conny's death is just the start of the horror.
3 Shoto Is Actually Endeavour's Son (My Hero Academia)
When Shoto is first introduced in My Hero Academia, he comes across as a very quiet and reserved person who sits at the back of the class. There is a short mention of the fact Shoto got into UA on recommendation so fans are shocked to find out Shoto's true origin.
It isn't until the Sports Festival that viewers are told that Shoto is actually the son of the number two hero, Endeavour. Until his battle with Midoriya, Shoto is shown only using his ice powers that he inherited from his mother and not his fire powers that came from Endeavour.
2 Sabito And Makomo Were Actually Ghosts (Demon Slayer)
During his training for the final selection exam, Tanjiro comes into contact with the siblings Sabito and Makomo. The pair of them seem to be there to aid Tanjiro in his training by sparring with him as well as offering advice. They were also taught under Sakonji and are believed to have passed their exams.
However, what viewers and Tanjiro weren't expecting to find out was the duo were actually ghosts. They were killed by the morphed demon and when Tanjiro finally defeats it, their souls can rest in peace.
1 The Truth Of 12 Years Ago (Fire Force)
One of the biggest mysteries in the first season of Fire Force is what happened to Shinra's family twelve years ago. All viewers know is that the fire supposedly killed Shinra's mother and little brother.
Unfortunately, the truth is that the fire was caused by his little brother, Sho. During the night, Sho's Adolla actually burst which sent their entire house up in flames. Not only was the fire itself a tragedy, it caused Shinra's mother to become an infernal. Shinra reports that he saw a Devil figure that night, but viewers weren't expecting that figure to actually be Shinra's mother.