This is too tangential even for one of my million in-text footnotes, so I'll put it down here.

In Edith's speech that sets up the idea that each person in the team will have their own personal ordeal (and therefore their own story arc showing us their origins), she mentions that Invisibles teams traditionally have a classical-elements-based structure: air/fire/water/earth, plus Dane being a wild card of "spirit". I don't think we ever find out who makes up these rules (the larger Invisibles organization is pretty far offstage in the series, exposition like this is usually brought in by someone like Edith or King Mob who just knows everything somehow)... but this one has a sort of comics-inside-joke aspect: it's been a very popular theory about the Fantastic Four since pretty much forever. I'm not sure Lee or Kirby ever actually said anything about whether that idea was intentional, but basically if you bring up the Fantastic Four, someone will eventually pop up to say that of course they're the elements and that's why there are four of them and everyone knows that.