I think you don't need 3x Shadow Tower. 1x is enough or even none, because it's usually kind of hard to actually win a challenge with this kind of deck.
"The Last of the Giants" and Varys (Core) seems counterproductive together with the big Wall, the discard will be flooded with trash.
Coldhands and the no saves plot is a great combo with the new Wall if you can recruit the saves from the original character that got removed from play.
I'd prefer more Ravens for more chumps that can die to military and more draw so maybe 2 of them.
Yep, that was a misclick. The Shadow Towers are supposed to be Roseroads. Fixed that in the latest version of the deck above. Added Coldhsnds per your recommendation to see how he plays out.
Are you sure you want to delete this decklist?