DARKNESS:
Won with devtal, dragon/gargoyle rush with BB, lost with dragon/gargoyle rush with RT, won with gargoyle/graboid novabow, lost with entropy/dark stall, won with devtal.
So they've got 2 devtals available, a BB/darkness rush, and a grabbow, and might be still able to do other stuff as well, but they can do those for sure. If we can counter devtal and rush, we're in good shape.
AIR:
Lost with OE/sanc stall, lost with fractal damsel/dragon/blitz, won with dragon/damsel/nightmare/dagger rush, lost with dragon/steal deck, lost with monoair dragon/tstorm/OE, won with adrenastaves/elite FFQ/deflag deck.
Catatitans might do well against air. It will fail against darkness unless we upgrade flying weapons; devourers will probably mean no air quanta ever. The DBH might work for either, but we haven't won with it, yet, and I'm not sure if scibra has the nymphs. I think a variant of the gravity/fire deck we used last round might do alright against darkness; conversely, we could run a gravity mark catatitans against darkness with AWs (obviously no fog then), and if they pick the BB deck, we'll laugh because they can't really BB our titans, unless they want an even fatter titan catapulted at them. Trouble is that would be vulnerable to steals, and the same issue arises with DBH; if discord is stolen, we will lose.
The other deck that might work is a gravity/darkness rush, just pack it with chargers and then all the darkness cards we have (steal/nightmare/dagger) and then we'd have a way around darkness's evil dusk/dagger with steal, as well as chargers, and nightmare would help against devtal. As trashduke mentioned, a couple random novas could be thrown in, too, if we're that worried about devtal.
We've also got the fractal charger lightning as a possibility. That probably fails pretty hard to devtal, though; not sure how it would fare against air. It would beat any stall they bring, but I don't know about a rush.
I'll let people think on that and see what suggestions/criticisms are leveled, and then we can worry about specific deckbuilding once we have a general idea what we want to do.