THE SCREAM CORE (NOT A GENRE OF MUSIC)
Haunting Scream appeared on the ladder around the time the Argenport nerfs, as it was well positioned to abuse the nerf to anti-void strategy strategies. The core interaction is to get a strong, cheap Infiltrator into your void, like Direwood Beastcaller or Gorgon Infiltrator, and then repeatedly trigger the Infiltrate effect with Haunting Screams and Dark Returns. Scream decks run tons of draw and small removal while assembling their combo. The skill ceiling is high in Scream decks and they take time to learn, but once mastered, tend to handle most opposition with ease. Storms are a good sideboard option as we *want* our guys to die too, so we can slap that sweet Flying & Charge buff on them.
THE ELF PADDING
Trying to make the new Elf Lord work within a Feln Scream shell. Skystrider's Ally ability is actually very strong in this deck and ~15 Elves seems like enough to make her worth the 4x. As more Elves become available, especially at the 2-slot, Skystrider is going to become a feature player of Feln Scream decks for her ability to immediately satisfy both branches of the Scream gameplan -- get a goon into the void, and draw the spell you need to buff him.
I'm noticing this shell is much weaker without access to Fire influence for Quarry (the most perfect possible interaction with Haunting Scream itself) and Combust (the most perfect possible interaction with Madness). Lethrai Skystrider acts like a 4-mana conditional replacement for Quarry, and Ashara Ruthless acts like a 3-mana conditional replacement for Combust. Being stuck at 2-3 mana happens often in 25-power Feln decks with no Vara's Favour and splashing F can still dig you through those bad starts. It feels like the deck needs too many things to come together in order to accomplish what Scarscream already does so much more smoothly.
NOTES ON CHANGES
I found myself mostly using Permafrost to pop Aegis, which Levitate is in for already. Additionally, it's dead against SST, which hoses our deck, and which I've been seeing a lot of. 2x 2-3 Health Flying units, or any form of anti-Flying, kind of hoses this deck. That's why I added in more Annihilates and the ChaCuns.
I was running Ashara for the Madness and GFanatic synergy, but at 3 power, 3 health, and needing to attack, I found even the 2 copies of her pretty unpleasant to run into - the payoff of 7 damage or killing 1 chumper is not enough for this deck that already needs a lot to go just right in the draws. Devour is much more dependable, pulling us into more of our core combo and the mana to play it.