The mystery of "The Blade Children" is a secret which has remained well-hidden, and has cost some their lives. After Narumi Ayumu's brother disappears in a search for the answer, Narumi is forced to unravel this mystery for himself. Join him in his investigation which will lead him to the secrets of the Blade Children, and to tests of skill which may prove to be fatal.
Dr Kenzo Tenma is a genius surgeon working in post-Cold War Germany who has a bright future ahead of him. He is admired by his colleagues, loved by his patients, and due to marry his boss' daughter, the beautiful Eva Heinemann. One day, when two patients in desperate need of emergency surgery are wheeled into his hospital, Tenma faces a terrible choice of saving the orphaned boy who came first or the mayor of Düsseldorf, whose recovery would raise the hospital's profile and boost his own career. Against the demands of his superior, Tenma does what he believes is right and saves the child. However, his decision not only damages his prospects, but unleashes a chain of events so horrific that it might have come from the depths of his worst nightmares. Laden with guilt, Tenma begins a journey across Germany in search of a formidable young man who will challenge his morals, his love for life, and his very sanity.
See beyond the average animation style in both of these shows, and you are treated to some deep thinking, twisted mysteries.
Most episodes are stand-alone, but all work towards the grand finale. Monster is much heavier going and more psychological, whilst Spiral may appeal to a wider audience.
Both main characters are struggling to fight against life, and the difficulties thrown at them from the protaganist. Further reading can be found in the excellent manga both are based on.
No one loves puzzles more than Kaito Diamon, and when it comes to solving them, he's the best there is. But when a labyrinth underneath his school leads him to an mysterious armband that can unlock his brain's full potential, he is put on the Puzzle Of God organization's radar as one of the children of Phi-Brain. Now he must push his mind to the limit as the P.O.G. challenges him relentlessly to their deadly puzzles. With a plethora of dangerous, laughable, creative, or down-right demented puzzles being thrown at him, will Kaito have what it takes to solve his way to victory or will he fall against the puzzles he adores so much?
Spiral feels a lot less shounen and is a lot more serious than Phi Brain - but both involve special 'children' and a whole mess of deadly puzzles, with plenty of analytical thinking and baddies to boot.
Saitou Yakumo is a young man with a very special gift: he can see the souls of the dead and communicate with them. When the aloof student isn’t duping his fellow classmates out of their money with fake card tricks, he takes on paranormal cases that pique his interest. Making use of his unique abilities, logical mind and his contacts within the police, Yakumo strives to solve each supernatural case he takes on and bring those responsible to justice. But when the youthful detective becomes the target of a sinister duo can he get to the bottom of their scheme before he is dragged into a world of darkness and hatred?
Although Spiral focuses more around the "Blade Children" (actual people, rather than spirits), the main characters' attitudes are very similar. They are both intelligent, although somewhat unmotivated, and they both use this intellect to "investigate" cases and solve problems.
Date Kyosuke is a young man with problems. After being stabbed by his beloved mother, he discovers he has a long lost sister -- Runa. She is the first of many relatives that he and others in the story find tied into the seeming chaos of their lives. Date embarks on a quest to find Runa, aided by his new ability to turn into a monster; all the while in pitched battle at almost every turn with agents of mysterious organizations.
Imagine a world where coal is the only fuel source and steam technology is highly advanced; in this world lies a fog-covered city known as Steam City. And under the cover of the mist, evil people use megamatons – steam-powered robots – to wreak havoc on the townspeople. Narutaki, a teenage detective with a brilliant mind, is the only person who can put a stop to these villains. With the aid of the nurse Ling Ling and the megamaton Goriki, Narutaki will stop at nothing to guarantee the safety of Steam City and all of its inhabitants!
If you liked Steam Detectives then you will also like Spiral because they are similar and both tries to solve a big mystery. The main characters are teenagers and both series have a girl who helps the detective.