Obscuring Blow has, imo, made backstab decks relatively great again. It juices a lot of value out of Sojourner, general attacks, and Hamon, plus when you combo it with situationally-relevant mobility spells it doesn’t push units out of Inner Focus range. I guess it can also save you a card if you want to all-in and use a Killing Edge right after, but I don’t think I’ve done that yet.
My current Kaleos deck also runs Beastmaster for counterattack-free frenzy memes.
EDIT: Here’s my list, just for the sake of chucking it in:
“soft cards” include Ethereal Blades and Heaven’s Eclipse. I might rather have a third copy of Sojo, KE, Spelljammer, and/or Hamon.