The Conversion Bureau: The Other Side of the Spectrum is a TCB fanfic formerly co-authored by Redskin 122004 and TB3, the latter of whom dropped out writing after the release of the chapter The Writes of Passage to focus on his professional writing career. It has since then evolved into a group project with authors Doctor Fluffy, ProudToBe, Drawdex, Kizuna Tallis, Beyond The Horizon, Rush, ThatClosetBrony, Inquisitor-Awesome, Jed R (author of The Avatar of Albion), VoxAdam, TheIdiot, Sledge115, Red Bomber, and Carpinus Caroliniana pitching in. Eventually, TB3 was drawn back in as a co-writer. Redskin has stated he wrote the story as a a deconstruction of TCB stories due to his personal dislike of the universe, particularly the stories of Chatoyance.
The series is notable for its large ensemble cast and highly detailed world building, with the co-authors expressing a dedication to make the story's world as thorough a deconstruction of the TCB universe as a whole.
Along with the main story, it also come with the canon side stories:
- The Conversion Bureau: The Other Side of the Spectrum, Side-story: Europe , focusing on Stephan Bauer in the early days of the war. (written by ProudToBe)
- The Conversion Bureau: The Other Side Of The Spectrum: Side-story: Starvation , which is about the struggles of refugees in Brazil. (written by Doctor Fluffy)
- The Conversion Bureau: The Other Side Of The Spectrum, Side-story-Asia , which focuses on the Asian front in the early days of the war. (written by Kizuna Tallis)
- TCB: The Other Side Of The Spectrum: Multiverse Journey , in which Discord tries to find earth and runs into some trouble.
- Case Files , an in-universe documentary detailing the HLF, PER and the PHL. (group project between redskin122004, Rush, Kizuna Tallis, and Doctor Fluffy)
- Calm Before the Storm , which follows the two weeks after the Battle of Boston, in all three worlds.(written by Doctor Fluffy)
- The King's Speech , an examination of what it means to be British when the Barrier has destroyed the British Isles. (written by Jed R)
- Last Train From Oblivion , a story taking place during the evacuation of Halifax, featuring Canon!Lightning Dust, TCB!Maud Pie, and TCB!Cheese Sandwich. (written by TB3)
- Shades of the Unsung, which focuses on Inkwell (a character from Calm), TCB!Sunset Shimmer and other original characters working behind the scenes to topple the Solar Empire. (written by TheIdiot)
- The Light Despondent, which focuses on Viktor Kraber and how he defected from the HLF. It's described as an "interquel" by its author. (written by Doctor Fluffy)
- Adrift, which details the story of a smuggler ship and its crew at the outbreak of the war, in the form of an interview with a pony crew member. (written by Sledge115)
- Joy to the Worlds, which focuses on the extermination of the reindeer and Hearthswarming Eve. (written by VoxAdam)
- The Many Faces of Mankind, an in-universe article made to be distributed into TCB!Equestria, interspersed with interviews with various human personages during the war. (written by Jed R)
- The Other Side of the Mirror, which focuses on the prime universe versions of the Asia Side Story ponies as they prepare for the final battle. (written by Kizuna Tallis)
- Once More Unto the Breach, which focuses on the survivors of the British Exodus. (written by Jed R)
- The Beautification of Lyra Heartstrings, a semi-sequel to 2014's Joy to the Worlds, it revolves around a religious council debating whether or not to beatify Lyra Heartstrings. (written by TB3 and VoxAdam)
In 2017, creative disagreements between Redskin and the other writers led to the original story being cancelled. The group has since begun work on a reboot titled SPECTRUM.
The story opens with a human male being tended to in the Ponyville hospital, being very uncooperative and shouting curses and insults at a very confused Twilight Sparkle. He alludes to things like "conversion bureaus" and "ponification." Later, Lyra Heartstrings curiously slips into the hospital to catch a glimpse of the man, who confuses her for another Lyra. The man, named Marcus, trusts the Elements of Harmony enough to tell them what is happening - his home world is being attacked by the Equestrians, and it's all being spearheaded by a Celestia gone mad. Upon realizing that there is an alternate Equestria out there committing these atrocities against the humans, Princesses Celestia and Luna and the Elements of Harmony vow to help Marcus and the last holdouts, human and pony alike, defeat their dark mirrors.
The Spectrum-verse (as referred to by its authors, calling themselves Team Spectrum), in a similar vein as The Conversion Bureau: Not Alone, seeks to deconstruct the TCB genre. It radically differs in tone, as Not Alone is (as described by author Starman Ghost himself) a "satirical take" on the genre; Spectrum is far grimmer, with the writers taking extra care to craft the world itself. The barrier is a deliberate attack on humanity by the alternate universe Celestia (who calls herself a queen instead of princess), and the massive displacement of humans is extensively explored. Earth's war against TCB-Equestria is very much an international affair, with the side stories detailing humanity and their allies' fight against the Solar Empire on all corners of the globe.
The main story's writer, Redskin 122004, has stated his main reason to write the story was a general response to his dislike of the genre, stating he felt The Conversion Bureau went against many principles he felt the series itself was founded on. In particular, Redskin has expressed a vocal dislike for Chatoyance's stories, a sentiment shared by many of the co-writers. Co-author and Asia side-story writer Kizuna Tallis has stated on her FimFiction blog that her story and her input draws influences from The Salvation War series, The Hunger Games series, and the Metal Gear Solid games, while Doctor Fluffy (author of the Starvation and Calm side stories) has admitted on his FimFiction blog that the works of China Mieville (particularly Perdido Street Station), Welcome to Night Vale, Elysium, District 9, and several first person shooters (especially Wolfenstein: The New Order and the Deus Ex series) have a huge influence on the atmospheres of his works. They also both have influences from Pacific Rim in their works and input on the main story. Parallels to World War Z are also drawn.
Unlike other stories, ponification and conversion is explicitly stated in the story to be a "half-existence" and outright destroys the soul of the converted. The newfoals are little more than automatons that praise the Solar Tyrant near constantly, and show no other emotion besides a hollow happiness.
The Spectrum universe has no set main character, but rather a massive ensemble cast that is all connected to each other. Aside from the human characters, there are two Equestrias as well (called by fans and the authors as TCB!Equestria and Prime!Equestria).
- Colonel Marcus Renee: The military leader of the UN taskforce and one of humanity's mightiest soldiers. A US Marine and once a veteran of the wars in Afghanistan and Iraq, Marcus is a very competent fighter, but the Conversion War has not been kind to him.
- Major Stephan Bauer: A leader of the German Bundeswehr forces, Stephan is known by his friends and enemies as the Knight of Germania. While he has his head together a bit better than Marcus, he has many of his own issues, the least of which includes that his whole home country had been lost behind the barrier.
- TCB!Lyra Heartstrings: A pony who believed in the existence of humans who later became TCB!Equestria's ambassador to the UK before she ultimately defected from her home country when she found out what Queen Celestia was planning. She founded the Ponies for Human Life (PHL), which started off as a peaceful protest group but grew into a bonafide military force in response to Queen Celestia's xenocidal campaign. As punishment for her betrayal, Lyra was eventually captured and executed. Despite dying however, her legacy continues to inspire and drive humanity and the anti-Solar Empire ponies to continue fighting.
- Viktor Kraber: A bitter and violent member of the Bundeswehr, formerly a member of the Human Liberation Front. His entire vendetta against the Solar Empire stems from how TCB!Pinkie Pie had ponified his wife and children at a birthday party. Doctor Fluffy has stated that Kraber's backstory serves as a metaphorical middle finger to Chatoyance's story "The PER: Michelson and Morely - The Speed of Right."
- TCB!Cheerilee: Another rebel fighter for the PHL, serving as a surrogate mother for numerous war orphans, a trainer to soldiers, and a leading figure within the movement. She is also the lover of Marcus Renee.
- TCB!Trixie Lulamoon: A spy and assassin for the PHL, skilled particularly in the use of knives, bombs and disguising (due to learning shape-shifting magics from her universe's Queen Chrysalis). She's also the lover of Stephan Bauer.
- The Ponies for Human Life (PHL): Originally a peaceful protest group started by TCB!Lyra Heartstrings, the PHL quickly became a thorn in the Solar Empire's side for its opposition to the conversion bureaus and the potion.
- The Dragons of the East: The main characters of the Asia side story, consisting of US Marine Porter Stanley, a former South Korean civilian Yon-Soo Park, former North Korean soldier Hyong-Jin Kang, Russian officers Khan Aitmatov, Ivan Melnik (both of whom are named after characters from Metro 2033), and Sergei Zaslavski, and ponies named Firebrand, Blizzard Flurry, Aquamarine Glimmer and Comet Tail. They are known as the greatest symbols of the Asian resistance, and have become rather infamous for their tendency to leave scorched earth behind their engagements.
- The Prime Equestrians: Having never fallen under the corrupting influences that caused the other Equestria to launch an attack on humanity, the Princesses, the Elements of Harmony, Discord (whose disgusted with the Solar Tyrant's actions) and the other ponies and races there all vow to help Earth in its darkest hour.
- The Equestrian Resistance: A mirror of sorts to the PHL, the Equestrian Resistance (aka, the New Lunar Republic) is a movement of ponies from the Solar Empire who recognize Celestia's gone mad and wish to bring Equestria back to a harmonious state once more. While they and the PHL mutually benefit from one another, their conflicting desires and interests do drive a wedge between the two groups and it's well known that both groups have spies planted within each other.
- Queen Celestia: Also known as the Solar Tyrant (or the Tyrant Sun), she is a Celestia gone mad, being little more than a power hungry and insane tyrant using harmony as an excuse to enslave and subjugate humanity. However, there are far darker and more sinister reasons behind why she wishes to convert all of humanity...
- Ponification for Earth's Rebirth: Like in other stories, they desire to speed up the process of Queen Celestia's campaign. They are quite possibly the most hated faction of the Conversion War, and are often killed as soon as they're found. Their membership consists primarily of hard-line environmentalists, misanthropes, and other people disillusioned with their lives on Earth.
- The Human Liberation Front: While they desire humanity's survival and the defeat of the Solar Empire, they are regarded as little more than thugs, whose rigid anti-pony stance has done more harm than good. They have targeted all ponies, including the human sympathizers, and are seen as much of a threat to the public's safety as the PER and Solar Empire are. Their membership mainly consists of criminals and other less-than-desirable characters, though a great many also have personal reasons for wanting revenge against the TCB!Equestrians.