Invisibility is going to be very popular with monsters who want to go out in the world.
As far as scrolls are concerned: Xeroxing them doesn't work. Carbon paper does, even on gray paper where the runes are barely visible for intellectual property reasons, and tracing a xeroxed copy also works fine; a simple spell takes about five minutes to make a stack of four. The spells are available in French and Spanish. There isn't a huge selection to start. But it's something.
They give Angela an after-school job tracing them according to demand so they have more time to discover additional runes and work out additional spells, and they put up fliers in the Avalon advertising a mail-order service.
Bella gets a car. It's a beat-up station wagon, but it works.
Bella has a small business, a vehicle, and a long-term career plan.
She sets about making arrangements to skip the eleventh grade, and Darren follows suit.
The two of them are adorably attached to each other. There is a lot of kissing. Savannah teases them a lot and Bella messes with her and Darren blushes.
By the time summer vacation starts, they have a stabilized price point, sufficient regular buyers, enough repertoire, and a nest egg of money that permit them to rent a small storefront and hire a teenage griffin to sell scrolls in the Avalon. They are on their way out (Savannah accompanying for kicks, Bella driving) to seal the deal and drop off a batch of inventory. Bright and early.
Bella, reasonably confident that Mrs. Adams knows what she's doing, alights next to Darren, close enough for him to hear her breathing.
"What," laughs not-Savannah. "Going to set me back to Dis? Good fucking luck managing that without killing the girl."
Another stare. "D-Don't, no, don't."
And if she's not, maybe fairy princess magic can heal even after the point where someone's technically dead enough to evict occupants.
Bella presses herself against Darren, hopefully comfortingly.
He doesn't know what he would do if she died here.
The demon phases out of Savannah. The teenager slumps back, unconscious, but alive.
Who's up for round two?
Mrs. Adams. Mrs. Adams is up for round two. She demonstrates by picking up the demon with sharp, sharp claws, and throwing him - it? - at a tree. She does not pull her punches, not when demons are involved.
Bella lopes up to Savannah, goes human-form enough to get at the scrolls on her person, pulls a healing one, recites its incantation from memory.
Darren notices Bella's attentions towards Savannah (by sound, not by sight) and smiles a little. He is perfectly happy to go help with taking out the demon that possessed his sister, now that it is firmly out of her...
The demon might, though. It becomes readily apparent that demons don't bleed. Instead, they ooze a red light that sticks to things before fading away. Some of the gore without none of the mess, how convenient. Because trying to clean up after the English teacher's demon-centered rampage would take hours.
It is not a clean fight. But it is very very fast. Also very one sided. The scattered pieces that remain of the demon fade away after, leaving nothing but the teenagers and the bugbear.
Bella goes back to invisibly leaning on Darren. She doesn't return to fullform; the invisibility will wear off any minute now.
Darren would try to take her hand, but - invisibility. "Thanks," he murmurs to her, instead. He checks over his sister with worry, occasionally giving Mrs. Adams nervous looks.
"Yeah, demon's - gone. Sort of dissolved after she tore it up. Love you too. Don't know yet, I guess. Darren, do you still want to go to the Avalon? And if so should we take Savannah home or...?"
"Admittedly, I kind of want to go home and curl up under a blanket now. Possibly while force-feeding Savannah chicken noodle soup."
"Okay. I can call - whatshisface, griffin kid, I have his name and phone number written down. We can go home."
"We'll say family emergency. Do - you want to come to my house, or go to yours? Is your dad at work, I can't remember."
"He's at work. I can come over to yours if you want but it would be reasonable for this to be Twins Time."
"I don't know how Savannah will react. We'll wait until she wakes up to decide? I mean - I'd want you there, because horrific trauma and I kind of want to cuddle you forever now, but I'm worried about her."