Because this story has a really outsize cast. I'll also note Signamancy here, because if you don't guess it then it's a wasted joke anyway. This includes minor details from notes that didn't make the main text.
Level is a pretty good indicator of utility, bearing in mind that that definitely is not the same thing as who would win in a fight, and I haven't playtested. I'm not including mastery, because it's not very important in terms of power. Most people class up at levels 3-5 and 6-8, although Ethereum has been hacking that rule.
I originally had this up to date with the text, while it was being serialised, for the benefit of those keeping up to date, but now that it's finished, that's just an annoying spoiler for newcomers, so I've rearranged it and cut out a lot of information.
'Jess' Genesis - Findamancer; from Worm; level 5. Has an emotionally sororal relationship with Charlotte. Respects Tom and May. Is contemptuous of Samedi and Cruller as feeble and unmotivated. Disliked Gus as a perv. Thinks Mal is too arrogant. Has a working relationship with Lecter. Former employee of Seed's; she still respects him despite being on opposite sides. Likes to play tank, accepting buffs and wading into the enemy to exchange heavy damage.
Samedi - Findamancer; Dr Facilier from The Princess And The Frog; 4. Introverted, but friends with Hedera.
Marvin Gael - Mathamancer; from The Hitchhiker's Guide To The Galaxy; 3. Loathes everyone without exception; this is mutual. Works for Ethereum as mission control, telling the others how likely their plans are to fail.
Pete Gyro - Turnamancer; Pete Burns from Dead Or Alive; 1. A shrinking violet, being low-level and not very respected. On bad terms with Revolver; was never a guild member. Likes turning prisoners and boosting city production.
'May' Harriet-May Stitch - Dollamancer; Harime Nui from Kill La Kill; 8. Chief Caster. Devoted to Tom, and something of a groupie. Finds Mal a nuisance who keeps trying to undermine her authority. Respects Jess and Koume as almost-equals. Calls Grim and Cruller her minions, and has them working from her designs to variously sew and darn cloth golems and fabricate gear; she doesn't really respect them, but isn't actively abusive. Has enough enchanted kit to be a solid fighter even without juice, and she has big bonuses against enemy dolls, but she's equally happy to either lead her own golems or provide kit for others.
Grim Virgo - Dollamancer; Kanaya from Homestuck; 4. Respects May as her deserved superior. Considers herself both stronger and to have a better attitude than Cruller, her junior. Is generally quiet and inclined toward keeping the peace; helping others rather than make waves.
Cruller - Dollamancer; Cruella de Ville from 101 Dalmatians; 3. Jealous of both May and Grim; a fan of Mal. Works as a support caster, making golems or raiment and the odd piece of gear.
Loony - Weirdomancer; Luna from Harry Potter; 4. Usually flies solo. Buffs other units as required; Jess is her favourite, but she switches it up regularly, and is also in charge of most of their mobility tricks.
Mal - Changemancer; Maleficent from Sleeping Beauty; 7. Considers herself a natural leader, and tends to patronise the others. An ambitious and very flexible caster.
Charlotte Pyotr - Changemancer; from Puella Magi Madoka Magica; 3. Best friend and imouto of Jess (I hope I'm using the word right: they're not actual siblings). Finds Mal to be a bully. Likes to transform into a giant clown snake form; more recently has taken to piling buffs onto Jess and letting her do the fighting.
Koume Rover - Dittomancer; from Legend Of Zelda; 6. Respects Tom a lot. Generally gets on better with men and likes most of them. Has a sister, Kotake, who's still in the MK. Dislikes most women, especially Lisa. During battle, she picks whoever's doing the most damage and copies them.
Sharkey - Lookamancer; from Lord Of The Rings; 3. Bromance with Cap. Is one of the steadiest people at the capital, on good terms with Miles. Is on bad terms with the Great Minds, but not as much as Lisa is; he's not a baddie.
Lisa Holmes - Thinkamancer; from Worm; 4. Wary friends with Akira, NV, and Hedera. Mortal enemies of the Great Minds that Think Alike; is formally a baddie. Works comms and manipulation of enemies, prospective allies, actual allies, bystanders, and anyone else within earshot.
NV Shift - Foolamancer; Envy from FMA; 5. Respects Lisa for her deviousness and Tom for his brutality. Thinks Flacutono is boring. Prefers to work alone as an assassin, but veils others if needed.
Flacutono - Foolamancer; from A Series Of Unfortunate Events; 3. Introverted. Thinks NV is an arrogant twit. Working mostly as a backup veiler.
Hedera Thurman - Florist; Poison Ivy from Batman; 3. Likes Samedi, James, and Gus, and most men. Doesn't mind Lisa. Dislikes Akira. Is on very bad terms with the MK Hippies. Is currently working agriculture, but resents this and has petitioned to be sent to the front to spoil enemy counterattacks.
Miles - Signamancer; from Phoenix Wright; 3. Likes Akira, despite her personality. Is on good terms with Sharkey and Lisa. On bad terms with the MK Hippies.
James - Date-a-mancer; from James Bond; 4. His craft lets him get on well with anyone; he particularly likes the ladies. However, he prefers to work alone. Deeply indebted to Tom for helping him out so much. Bad terms with the MK Hippies. Usually rides out taming feral creatures on Sharkey's intel.
Tom the Marvel - Shockmancer; from Harry Potter; 5, 6 after croaking Hiller. You should remember this one. In a groupie relationship with May. Appreciates his followers, but it's ambiguous whether he likes them so much as he finds them useful and figures they'd be more useful if they liked him. On bad terms with all the guilds. Prefers to be a front line fighter, blasting anything he can reach, but is a solid planner and manipulator.
Arthur - Croakamancer; Arthas from Warcraft; 2. Friends with Gus, Koume, and Mal. Loyal follower of Tom. Dislikes Lisa. Raises corpses and sends them in with no real strategy, with the tacit understanding that they will deal damage or at least screen for long enough for someone else to think of a plan.
Cap Doffer - Hat Magician; Courtyard Droll from Homestuck; 2. Bromance with Sharkey. Likes Loony and Akira, who both model for him sometimes. Joined Ethereum for the chance to make awesome hats.
Gus Tone - Rhyme-o-mancer; Gaston from Beauty And The Beast; 4. Likes Arthur, Koume, and Mal. Acts as a quasi-warlord, providing dance-fighting bonuses from the front.
Akira Tsu - Luckamancer; from WIXOSS; 3. Is too psychopathic to have friends per se, but she's fond of Miles and thinks Lisa is a viable co-conspirator. Catty rivalry with Hedera. Prefers to stay atop a tower, providing passive bonuses to the rest of the side, but has recently begun considering her discipline's potential.
Dr Lecter - Healomancer; from Silence Of The Lambs; 4. Secretive, but he probably likes Arthur, Gus, and Koume. Dislikes Samedi and probably Lisa. Has a working relationship with Jess, with whom he combos nicely.
King Jasper - warlord King of Pro Toast; Jasper Fforde.
Thursday - PT's Chief Warlord; Thursday Next; 8.
Magic Kingdom (nominal spoilers)
Seed Rick - Findamancer; Cedric from Harry Potter; 8. Prefect of the Sett (Findamancer guild). Jess' former employer.
Red Catchem - Findamancer; protagonist of Pokémon Red; 7. Master-class and Sett 2iC.
Misty Kismet - Mathamancer; cameo of VeryFuzzyLogic; 2.
Revolver Oscillate - Turnamancer; Revolver Oscelot from Metal Gear; 9. Head of the Turnamancy guild.
Eternity Hourglass - Turnamancer; general timey-sounding name; 5. Guild member.
Mark Thread - Dollamancer; threadmark; 3. Neutral lodger in Ethereum.
Dolly Knockers - Dollamancer; Dolly Parton; 2. Neutral lodger in Ethereum.
Lady Jasmine - Dirtamancer; the mineral; 11. De facto leader of the Dirtamansion.
Zoe Iyt - Dirtamancer; zoisite; 3. One of the Iyt clan.
Sabrina - Changemancer; Puella Magi Adfligo Systema/cameo of DrDM; 5. Mad scientist and Railgun's housemate.
Hal Jones - Changemancer; Howl from his Moving Castle; 4. Neutral lodger in Ethereum.
Jack Pollock - Dittomancer; Castor and Pollux/Jackson Pollock; 8. Socialite.
Gemma Nye - Dittomancer; the zodiac sign; 2. Socialite.
Meekay Air - Lookamancer; "Magic Kingdom Air", sounds like a radio station name; 2. Member of the Barnacle Battalion.
Mewlin Pendwagon - Thinkamancer; Merlin; 13. Headmaster of the Great Minds. Non-personal mortal enemy of Lisa the baddie.
Daisy Chain - Florist; Princess Daisy from Mario; 10. Respected senior among the Hippiemancers.
Ozec Shéol - Signamancer; pun on metrosexual, actually more like The Matrix's Merovingian; 9. Makeover guru and noted philanderer.
Undine Eros - Date-a-mancer; Yurippe from Angel Beats!; 2. Leader of the Barnacle Battalion.
Volt Eyre - Shockmancer; Voltaire; 7. Neutral who spends his time making Shock wands.
Railgun Ampère - Shockmancer; from A Certain Scientific Railgun; 5. Qualified law enforcer employed by Knocks Bank.
Black Betty - Croakamancer; 2. Fence living in the Carnyvale.
Dora la Fey - Hat Magician; Fedora; 10. Socialite.
Sophie Indie - Hat Magician; from Howl's Moving Castle; 2. Neutral lodger in Ethereum.
Rex de Léon - Carnymancer; Kings of Leon; 4. Ringleader of the Carnyvale.
Wunsun - Carnymancer; cameo of theonesungod; 3. Doer of whatever needs doing.
Floonit Raspem - Carnymancer; Flunitrazepam; 1. Carnyvale hustler.
Plum Dirigible - Rhyme-o-mancer; Led Zeppelin; 7. Member of World Orchestra, Rhyme-o-mancer guild.
Jay Pop - Rhyme-o-mancer; generic anime idol singer; 5. Member of World Orchestra.
Matt Showbiz - Rhyme-o-mancer; Matthew Bellamy; 5. Member of World Orchestra.
Eve - Rhyme-o-mancer; Evanescence; 3. Member of World Orchestra.
Paul Apostolopolus - Rhyme-o-mancer; the Beatles; 3. Member of World Orchestra.
Rictus Lee - Rhyme-o-mancer; Rick Astley; 2. Member of World Orchestra.
Dunkel Mendit - Healomancer; Dunkel Mentat cameo; 4. Paramedic.
Penny Arcane - Moneymancer; Penny Lane the Beatles song, and Penny Arcade; 10. CFO of Knocks Bank.
Dismal Births - Moneymancer; Mary Poppins; 6. Knocks Bank employee. Professional; dislikes Akira.
Peso Ruble - Moneymancer; two worthless currencies; 1. Knocks Bank employee. The guy who gets all the worst work.
Ethereum latecomers (some spoilers)
Belle, as of 3 - warlord; vaguely from Beauty And The Beast and Harry Potter; 1. Generally neglected by the casters. Prefers to be a battlefield leader.
Riley, as of 4 - Healomancer; from Inside Out but mostly Worm; 1. Tom's little girl. Loves May, who spoils her. Gets along well with Saito. Thinks Pete is okay, but too shy. Is surprised by how skittish Jess and Lisa are. Becomes friends with Charlotte, despite Jess' reservations. Depending on what needs doing, is either a battlefield healer, Erfworld's first ever Healomancer golem crafter, or trying to multiclass.
Saito Pomp, as of 5 - Croakamancer; Eucliwood Hellscythe of Is This A Zombie?; 1. Likes Riley and James.
Jane Silver, as of day 8 - warlord; Long John Silver; 7. CW of Mugmonster, until pwned by Loony. Dislikes Riley.
Suss Try, as of day 10 - Foolamancer; Emerald Sustrai of RWBY; 4. Originally of Bell-End and later of Pro Toast. Old friend of NV.
Others (nominal spoilers)
Brawndo - Shockmancer; spoof spoof sports drink; 4. Member of unknown slaver side.
Ninjette - Foolamancer; hackneyed female ninja; 1. Member of unknown slaver side.
Malcolm Braford - Turnamancer; Malcolm Turnbull; 7. Pro Toast's Chief Caster.
Prince Tastar - Pro Toast warlord; a toaster/Tassadar from Starcraft; 7.
Tagg - ?