Mystery the Hedgehog (franchise)

Mystery the Hedgehog was the collective name of a series of Sonic the Hedgehog fanfictions created and planned by Ryan Nurse between 2005 and 2013. Of these, only one, Mystery: Ultimate Darkness, was actually released, being published on DeviantART between May and October 2011; this was Nurse's first publicly-released literary work, pre-dating The Hospital Visit by a year. The remainder were either never written down, or deleted due to their poor quality.

The series centered around the eponymous Mystery the Hedgehog, Nurse's main fancharacter and the precursor to Project Nero 's Nero. Earlier works included characters from the main Sonic canon, but starting with Ultimate Darkness, the main cast consisted solely of fancharacters, and the unreleased Mystery: The Alliance would have excised all canon elements entirely. In August 2014, however, the franchise was cancelled, and folded into the new Project Nero franchise, making it the first of Nurse's projects to be officially cancelled.

Initial series
The first instalment of the franchise was Adventures of Mystery the Hedgehog (AoMtH), a series of roleplay-style stories written by Nurse around 2006-07, and comprising 24 episodes across four series. AoMtH centered around Mystery, an extremely powerful "Second Ultimate Life Form" from another dimension, who had been aboard Space Colony ARK at the time of Maria Robotnik's death and had recently awakened from a 50-year stasis. Though initially vengeful, he eventually agreed to work with Sonic, Shadow and his friends as part of "Sonic Team", battling Doctor Eggman and other miscellaneous threats.

Despite its poor quality, pandering to many of the archetypes of bad Sonic fanfiction, AoMtH laid down much of the groundwork for Project Nero, its ultimate successor. Lebánon the Echidna, introduced in Season 2 as Mystery's love interest, would eventually become Alexis Moreau; Energon the Lightning, introduced as his rival, would eventually become Ren Nishikori; Ripple the Porcupine, a minor one-shot character, would later become Rio.

The sequel to AoMtH was Mystery LAPD, of which little is known, as it was never written down. However, it is thought to have toned down the intense battles and emphasis on Mystery's powers that dominated AoMtH. It also introduced Solstice the Fox and Melody Mongoose, who would later become Summer Snow and Melody Montrose respectively.

Reboot
In 2010, Nurse decided to undergo a significant reboot of the entire Mystery fanon, creating a new series named Mystery: The Legion. All canon elements were excised, the characters' powers were nerfed significantly, and their appearances, personalities and backstories were significantly altered. Lebánon and Energon were completely replaced, becoming Alexis the Hybrid and Lotus the Android respectively; new character Forza the Fox was also added, forming the precursor to Nero 's Joey "Forza" Frazetti.

Before Ryan could start writing Legion (later renamed Mystery: The Alliance), he began writing another fanfiction in collaboration with schoolfriend Aaron Middleton, which became Mystery: Ultimate Darkness. Set in an alternate continuity, Ultimate Darkness retained several canon elements (Dr. Eggman and the Chaos Emeralds both appear), and introduced two new characters: Carmen Lupez, who would later become Carmen, and Adachi, created by Middleton. Written in twelve parts between October 2010 and May 2011, it was later published with several alterations on DeviantART between May and October 2011, becoming the first project to be publicly released in any format. It also remains the first and only project in which Nurse openly collaborated with another writer.

Though Lee planned a second series of Ultimate Darkness, it was never written, and instead Nurse planned his own sequel, Vast Darkness, in which the group would travel into space to destroy an evil alien race and prevent Earth's destruction in 100 years' time. A third part of the trilogy, Total Darkness, was also considered but never formally planned. Nurse also planned Mystery: Requiem, a spin-off from Alliance in which Mystery attempted to track down an ex-love of his that had been kidnapped in Brazil by sex traffickers, with the hedgehog's backstory being explored in more detail. The latter became a story arc of Project Nero, while the former two were cancelled and eventually became Project Nero: Recursion.

Cancellation
Nurse never started writing Mystery: The Alliance beyond a few paragraphs, and in mid-2014, in response to the increasingly negative perception of Sonic fancharacters, he began to consider either cancelling it, or humanizing the characters. In August 2014, he declared that Alliance, and the Mystery universe as a whole, would be turned into a new series, Project Nero, reusing many of the planned storylines but with humanized versions of his fancharacters. The Mystery the Hedgehog universe has thus been officially scrapped, however, its characters will still appear in When Worlds Collide, with Mystery available as a playable character.