One really impressive thing about the first chapter of campaign 1, now that it's wrapped up, is how much character backstory they've already revealed and started exploring. Most characters obviously have more details to be filled in (for example, several characters have family members about whom we know very little), and it's possible that there are some major reveals that haven't really been hinted at, but right now, it doesn't feel like there are any huge gaps or questions in character backstories.
The two exceptions that I can think of are
The question of what exactly went down between Julien and Thjazi during the Battle of Maharlian Falls, which appears to have had a huge impact on Julien's character (and his relationship with other characters) going forward. This seems like it could very well come to light as Julien travels with Thimble, who may have been there. There also seems to have been something that went down between Julien and Tyranny, although it's not clear that this was a major part of either one's backstory.
Aspects of Teor's backstory — namely, his complex relationship with Cyd, the source of his and Cyd's power, and what made a nama (which we have barely seen this campaign) join the Falconer's Rebellion. I think some of these questions may be answered as part of larger worldbuilding, but others have probably died with Teor.
Either way, that's a lot that's been answered. When I think of episode 31 of C2, there were still some huge character backstory elements that had been hinted at but not yet revealed — for example, the Veth reveal, Beau's family, Orphan Maker, etc. And that's despite C4 having way more characters!
I think the reasons that we already know so much about the characters' backstory are
the flashbacks, both in the cold opens and occasionally at other times, which have given us a lot of character backstory and probably motivates players to interact with those backstory elements as part of the present-day plot;
how well-integrated the characters are into their worlds, so that character backstories are often parts of the present-day plot; and
Brennan's articulated preference for doing big reveals early, because the most interesting part is the fallout of the backstory, not the backstory itself.
Anyways! Just very cool!
From @featherquillpen:
I would say there are still some major backstory questions that remain. A couple that I've been chewing on are: a) if Murray is a gem heiress from a mining fortune, why does she clearly have so much experience with poverty and dispossession and the criminal life? what happened there?, b) Why do Bolaire and Vaelus know each other and why does she hate him?, c) why did the bond between Wulfric and Kattigan ping as completely unlike anything Thaisha had seen before when she tried to speak to Wulfric in the Overture?
Good points! I think all of those have the potential to have major backstory reveals within them, or the potential to have easier explanations.
For a) it's possible (I'm not sure where I first saw this theory) that Murray was lying about her family's fortune (or even about being part of that family). I've been just assuming that she and her family, as immigrants, fell on hard times, and that their connections meant less in Dol-Makjar than they had in the Sunset Mountains.
For b) it's possible that Bolaire and Vaelus have a more complicated backstory, but I've been taking Bolaire at his word that he helped her access the city to fuck up Thjazi's life. Her disliking him wouldn't be super surprising, since (especially at the beginning of the campaign), she came on strong against most people.
I think c) is the one that strikes me as containing the most potential, since a major theme of C4 appears to be exploring the different types of magic present in Aramán. Kattigan's magic appears to be most closely aligned with that of the druids (both in terms of flavour and mechanics; he has the Druid Initiate feat) but he doesn't seem particularly aligned with any druidic order. With regards to what Thaisha sensed, from episode 2:
As you attempt to speak with this animal, a potent magical bond between Kattigan and Wulferic. I'll put it this way. On a nat 20, if you attempt to speak with Wulferic in this moment, it'll be the second potent magical thing you have touched this evening. [...] Wulferic may not be wild in the ways that a typical animal that you would speak to would be. There is something that he is within that is potent and magical.
I don't sense that the Kattigan & Wulferic bond is necessarily "completely unlike anything Thaisha had seen before" but it is somewhat surprising that she, as a druid, wouldn't recognize it as a type of animal companionship, and, of course, that it's so potent. This could definitely indicate that there's a thread that they'll pull on later. At the same time, I could absolutely imagine that they simply have a very strong bond that's the relationship of both friendship and magic, and that that magic in particular is a form of unschooled/self-taught druidic magic, which is why it's not particularly recognizable to Thaisha.
In summary — I think all three of those, and especially c), have the potential to be major backstory reveals, but all of them have the potential to be a little more mundane. On the other hand, we know that there's something there with regards to Julien & Thjazi and with Teor's magic, as characters have brought it up very explicitly.
