Thank you so much, this is all very useful!
One Shot, I’d like to put some mystery behind the mishap, probably some cospiracy. And the player character, Firmus filius of Guernicus, will be compromised.
A first draft:
Bonissagus and Mercere are working on something in their lab.
Someone wants to harm one of them, or both, or their work.
Firmus is working there as a lab assistant and does something that triggers the disaster.
He may or may not know who set him up.
He probably doesn’t know why this person wanted the accident to happen.
He may or may not know what the consequences will be. If he does, he’s probably been blackmailed into it, or threatened, or enchanted, or persuaded, or bribed.
Anyway, for some reason the details about the accident are not revealed, and Firmus isn’t pubblicly blamed for it. Nobody seems to be very willing to talk about what happened and why. Bonissagus takes it on himself, probably to stop the talking, and maybe because he thinks Firmus has not done that on purpose, and he doesn’t want to spoil a promising apprentice.
Bonissagus is extremely sorry for his friend Mercere, even more than expected. Maybe he knows it’s also his fault. What they were searching in that lab? Something that no one must know about? Is it something that called for what followed? Has Bonissagus put Mercere (and himself) in a dangerous situation? Or viceversa? Maybe the lab activity isn’t the point… Maybe someone wanted to kill Bonissagus for political reasons. Or Mercere for private reasons.
The mystery lingers, and sooner or later Firmus or the whole troupe will be pulled into it.
In the meanwhile Firmus keeps on with his study and passes the gauntlet. He always does the right thing, behaves well and displays wisdom and diplomacy, earning the respect and acknowledgment of many magi. But there are people around that know at least a bit of what happened. The one/s that set him up, Bonissagus, Mercere and their closests friends, and someone else who may have overheard. Every now and then, someone looks at him with a less than friendly stare. Sometimes a word is spoken to remind him of what happened. All this won’t go away until the mystery is solved.
I'm still working on the details and I would appreciate any idea, especially about the motivations behind the people using Firmus as their puppet.