Janna Russo views life in her hometown of Echo Creek to be pretty boring, with its disappointing lack of mystic portals, eldritch abominations, or any other otherworldly elements. And the troublemaker's years of attempts to liven things up have all proven to be failures in the long run. Thankfully, that all changes when one of those aforementioned mystical portals she's always dreamed of suddenly opens up in the sky and spits out a gigantic spell book into a nearby dumpster. With resident safe kid Marco Diaz along for the ride to help mitigate all the inevitable damage, Janna is now on the path to become a sorceress who can finally bring some fun to her mundane life. Of course, this begs a few questions: where did the Magic Book of Spells come from? Why is Janna the only one able to read it? And who used to own this thing anyway?
The fanfic began in October 2016 and had entered the second of a planned three-season Myth Arc before Zim and SKL began writing a revised version of the fanfic in August 2019 entitled Janna vs. the Forces of Darkness, which constitutes Chapters 30 and ownward. The writers run a Tumblr over here that features various pieces of chapter art, additional pieces of worldbuilding, and writing updates.
Janna vs. the Forces of Evil provides examples of:
- Alternate Universe Fic: Rather than sending her to Earth to control her powers, Star was sent on a year-long pilgrimage across Mewni to do so instead. The chase for the wand being localized to Mewni results in Higgs becoming Star's close companion instead and dying when the duo confront Toffee, as well as Star going missing shortly after. Toffee still goes on to control Ludo's body on-and-off, usurping the throne and furthering his plans to access the source of all magic, but the Magic Book of Spells somehow finds its way to Earth and ends up in Janna's possession.
- Breather Episode: The intermission chapters, which serve as brief side-stories with little plot relevance. "Janna and Marco Go Bowling" is Exactly What It Says on the Tin, "CDC Extra Scenes" is Jackie and Buff Frog going to a book club, and "Christmas Caroline" is a Christmas Episode that bridges the first two seasons.
- Cooldown Hug: Janna gives Marco one in "Digitize Me, Diaz" when she realizes her request for him to scan the book led to him almost hitting his Rage Breaking Point.
- Dancin' in the Ruins: Janna's initial reaction to the horde of zombies she's summoned as her first spell in the original version is to remark how cool the entire situation is. Even as things worsen, she questions why she'd ever want to undo it... until everyone else has been turned and she's trapped in the band room. The recut version still has her excited throughout the entire incident, but too exhausted from casting the spell to enjoy any of it.
- Disneyland Dad: Janna's father. While nonexistent and unnamed in the original fanfic, Darkness has Horatio as an overseas black market dealer who frequently sends any mystic objects he can find to his oldest daughter, who is the only member of his family he chooses to interact with.
- Driving Question: What happened to Star Butterfly?
- Emotion Control: "Date Night" has Janna practicing personality magic under Glossaryck's insistence, though he warns never to mess with love and hate outside of a last resort, due to how difficult and volatile they are to manage. Janna messes with them anyway.
- Everyone Calls Him "Barkeep": The Janitor. His real name is unimportant.
- For Want of a Nail: "What if the magic instruction book was sent to Earth, but Star stayed behind?" As noted above, there are a number of other changes beyond this, but this is the main question the story is built upon.
- He Who Fights Monsters: "Punk to Preppy" has Janna cast a spell that slowly changes her appearance, personality, and behavior in order to become the most popular kid at school as a form of revenge against Brittany for picking on her and Marco. Marco is eventually forced to get Jackie involved in order to make her see reason.
- Friendly Enemy: Marco and Janna's relationship at the start of Darkness, with this having been their dynamic since they first met in 2nd grade.
- Ingesting Knowledge: Ishkilthul, Demon of Knowledge, does this. Janna ends up trading him the internet for the answers for her math homework, allowing him to suck up all the information on the internet and place anyone who was using into a comatose state as he sucks up their knowledge as well. Even after she and Marco get him to stop, the internet is still gone for the rest of the fic.
- I Warned You: Glossaryck, despite preferring to play the role of Eccentric Mentor, still frequently warns Janna (and sometimes Marco) the dangers of messing with magic. How much guidance he's willing to give in order to fix a mess after they inevitably fail to heed his warnings depends on the situation.
- Jerkass Realization: Janna has one in "Date Night", realizing how bad of a friend she's been to Marco after Jackie summarizes everything that has happened in the past few days.Jackie: So you went on a date at his house even though you didn't want a date, because it would let you make fun of your best friend, and then when things went exactly like you'd think they would, you used magic to make everyone not like you?
Janna: (mumbles) Well, when you put it like that...
- Magic Genetics: Moon reasons that Janna being part of some royal bloodline is why she's capable of using magic without a wand, to say nothing of how much magic potential she has. Janna later meets another human who's also capable of wandless magic, who reveals that magic has been taught in his family from father-to-son for generations.
- Muggle Best Friend: Jackie Lynn Thomas. While she does occasionally get involved with Janna and Macro's magical antics, she's usually off doing more mundane things when not serving as an additional voice of reason for our resident witch.
- Nice Hat: Both Janna and Joleen wear olive-colored beanies.
- Noodle Incident: Among all the things Janna has done to make the lives of the janitors, cafeteria staff, and librarians at Echo Creek a nightmare is an unspoken incident that only makes them loathe her more.Janitor: I... try not to remember. A thousand cuts demand a thousand in return.
- O.C. Stand-in: Janna inadvertently became this, as the canon character ending up becoming an Ascended Extra. While she shares basic personality traits with the show's Janna, the Janna of this fic has the last name of Russo (rather than Ordonia), is of Italian descent (rather than Filipino), and is raised by a single mother alongside a younger sister (rather being an only child with a mother and father). She also has a friendlier relationship with Marco, with the duo quickly coming to see each other as best friends over the course of the fic (whereas the canon Janna wouldn't vocalize anything of the sort until the series finale).
- Opposites Attract: The reason why Marco and Janna are drawn to each other, as they both have parts of themselves the other is missing. Janna has the unpredictability and excitement that Marco craves in his life, while Marco has the emotional openness and rational thinking that Janna sorely needs (whether she realizes it or not).
- Positive Friend Influence: Marco and Janna are this to each other. Jackie silently notes that Janna stopped getting into as much trouble as she usually does when she started regularly hanging out with Marco, while Marco's parents point out that he's now more outgoing and confident thanks to her presence.
- Re-Cut: Janna vs. the Forces of Darkness serves as this. A number of events are given greater contextualization and meaning within the larger story arc, alongside other writing tweaks, and efforts are made to separate the fanfic's lore even further away from the show's canon than before.
- Reality Ensues: In "Pinkslipped", Janna accidentally demolishes her home. Janna can't instantly fix the issue because she isn't powerful enough to simply magic up a brand new house, so her family is fully resigned to homelessness until Marco's family (alerted by Glossaryck) offers to take them in. Later in the chapter, the police get involved when Joleen tries to rob a bank in order to fix both this and their financial situation; the only reason she gets off with just a warning is because no one wants to figure out how the paperwork for "robbery by magic portal" should go.
- Riddle Me This: "Goose Chase" has Janna secretly give Marco a riddle as a prank. Except that the riddle has no answer, in order to confound him even more. Unfortunately, Marco is still able to solve it and thinks its a love letter from Jackie to boot, forcing Janna to spend the rest of the day thinking up additional fake riddles in an attempt to make one that's too hard to solve, so he doesn't get heartbroken.
- Ship Tease: Marco and Janna. As early as the second chapter, the knowledge demon Ishkilthul remarks that Janna should be nicer to her future husband. Other characters, such as Joleen, regularly refer to them as a couple as well. Later on, Marco's parents say that the duo are destined to be together, as they themselves had a similar "prankster and victim" relationship in high school. Janna fears that she may have such feelings, at the very least.
- Spell Book: The Magic Book of Spells, natch. Janna quickly decides to copy the entire thing to her phone so she doesn't have to constantly lug the gigantic tome around.
- The Stations of the Canon: Surprisingly averted for this genre of fanfic. Due to the backstory and lore changes, the only chapter that mirrors any canon episode to a substantial degree is "Monster Arm", which is the JvtFOE version of... well, "Monster Arm". And after the show's third season, Zim announced that the fic would be going forward "independently of whatever asinine decisions the show makes."
- The prologue for Darkness has an alternate version of "Storm the Castle" occur, with Higgs taking the place of Marco.
- Struggling Single Mother: Florica Russo, who is constantly working in order to provide for her two daughters.
- Take That!: Zim and SKL are pretty open about their dislike of the actual show from season three onwards in the authors' notes and on their Tumblr, to the point that the former wrote what amounts to an essay about how awful that season was. This dislike occasionally slips into the fanfic itself.
- Pony Head, one of the show's most base-breaking characters, is never seen. She's only described with phrases like "the worst person you know multiplied by cancer" when others ask about her.
- In "Unfiltered", when Marco and Jackie go on a date and end up at a carnival pier, the former notes that if their lives were a TV show, despite just having spent a fantastic time together, this would be the moment where they break-up. Jackie laughs and immediately says that such a thing would be terrible writing.
- Trapped in TV Land: In "The Second-Hand Crusade", Janna accidentally triggers a spell that does this when at a table read for the chapter's titular cartoon. Her, Marco, Jackie, and Joleen are forced to play out the episode's events before being allowed to leave, and all of them (sans Janna) are compelled to think they're their respective characters as well. Joleen, who's a huge fan of the series in question, loves every second of it.
- The Unapologetic: Janna, who usually sees whatever damage her antics has caused as a bonus or doesn't understand why she would even have to apologize. Later on, she realizes that the fact Marco is one of the few people she's willing to apologize to is proof that he had become her best friend.
- Voice Changeling: The swamp that Tom and Janna visit has creatures that do this, mimicking the voices of a victim's loved ones to lure them into drowning into the mud.
- Zombie Apocalypse: Janna does this as her first spell, summoning reanimated corpses that quickly transform much of the student and staff into the undead as well. In the revised version, it's a plastic dinosaur toy that starts the outbreak.