One of the things that continually amazes/fascinates/makes me obsessed with them, is how parallel they are to one another. They have the same strengths and flaws, expressed in two different directions (most of the time). And I think that's one of the reasons I 'ship them rather than another kind of relationship (and I LOVE that the books leave it so open to interpretation, yay!) because to me, siblings come from the same place, and go (or are shaped) in different directions - you can see the stamp on them of where they've come from and that's their similarity. But in this case, they started out from radically different stamps (you can't really *get* more different than their backgrounds) and found the same (or are finding the same) shape.

Which is also why I keep waiting for Kate to make some kind of stupid-ass decisions about things, because that's all part and parcel of the character traits that they share. (The ego, the daredevil recklessness and so on that make them do what they do even though they're non-super-powered and squishy.)

:D