I should gather everything I've collected about my handful of templates into a dedicated thread like the Kids Are Doing These Days, but I am (still) lazy and (mostly) haven't gathered them.
Characters:
Arthur and Suzy
Arthur: Arthurs generally go through life not standing out. They're clever but not driven, easygoing and good at making friends and allies. He's usually adopted by a couple of somewhat accomplished professionals and, if nothing interferes, he'll follow them into their profession. So usually he has to have a plot thrown at him such that he either can't pass up the opportunity or has to solve it to get back to a normal life. Luckily, he has a connected template who is pretty happy to force him at a plot!
He has attractors toward unknowingly being the heir of something and/or being handed a crown, and is loosely named after a historical or mythical king where possible. Unless events seriously conspire against him, he will accumulate a backup cast. If he is magically talented, he will probably have a talent for working with steel or protecting against magic. (Original: Arthur Penhaligon, Keys to the Kingdom)
Suzy: Suzy has no chill. She is also one of the Gryffindoriest Gryffindors to ever Gryffindor. She decides that something is Important and will charge straight at it before actually thinking about it. Pros: gets stuff done. Cons: gets her hurt. She has bipolar and ADD tendencies, though whether these are strong enough to interfere with her life varies. She has basically no respect for authority that isn't her friend, and will turn herself into an authority if she can. (So she will also try to get herself a backup cast.) (Original: Suzannah 'Suzy' Turquoise Blue, Keys to the Kingdom)
When they appear together, which is usually, they balance out to having restraint but also goes out looking for problems to solve. (I think TvTropes calls this Red Oni/Blue Oni.)
Suzy is generally older and is more likely to be magical/special if they are have different levels of talent. They will be childhood friends most of the time, lovers sometimes, rarely actual siblings but if there's a reason a bunch of kids are raised together, that's fair game (orphanage or whatever). They'll always be emotionally close, and if there's anything like 'drift compatible', they will be that.
Their usual supporting cast have names and rough personalities and will probably recur: Therese, Aidan, Peter, Vito, Hui, and David. The most detailed version of them is Amestris.
Appearances so far:
In Lyric with Marri, Arthur/'Zach' Black and Suzy Blue were in the same orphanage. Art has a band, Suze guest stars sometimes, and they host stray homeless kids on their couch.
In Cloudbank (Transistor version), Red is a Suzy and Arthur is stuck in the Transistor. (If they had a supporting group it's all gone before the story begins.)
In Amestris (FMA: Brotherhood), Carl Magister (Arthur) is the Blade Alchemist and Anna Greyhound (Suzy) is the Wildfire Alchemist. They have a bunch of subordinates.
Drop-In Prompts:
Red and Transistor can appear in Milliways at a couple points in the canon Transistor plot easily (or other times, probably)
The Transistor can approximate a portalsnake if it likes, it can create simulations of entire worlds and possibly do many other things.
Amestris can summon someone in an alchemy research accident and Carl and Anna (and their officer team) could find that someone.
Carl or Anna could vanish in an alchemy research accident and appear wherever.
Any prompt I've already used anywhere.
If any of these sound interesting, I'm always on google chat at the obvious email address.