The build around for this week is
Endra, Champion of Shavka. Her pre-nerf form (2FFF instead of 3FFF) was the most broken card in all of Eternal's history, but since her nerf she has only seen sporadic play and the combo decks built around her haven't really seen a lot of success. I don't think this version changes that completely, but some new additions make the deck better than I expected. So far I'm on a 12:6 score, which is pretty decent for brewlette standards.
The most important new card is Eager Youth: If the only unit in your deck is Endra, you will always reduce the cost of one of her copies and a 1-power Endra is much easier to combo with. You can't play 4 copies of Youth in your maindeck and you can't play any Merchants/Smugglers because additionaly units would mean that Youth could miss Endra, but you can still play 8 ways to get Youth from the market (Salvo and Delivery). The other new additions are Marks to smooth out the powerbase (which is still a bit clunky, but that is to be expected when you want to get FFFTJ consistently by turn 3 or 4) and Seek Refuge as a new way to bounce Endra (it really shines if you get 2 Endras in rotation, otherwise it's just a worse Safe Return, which is still fine).
The general idea is to just draw Endra (you have Rujin's Choice, Rise to the Challenge and a market copy of Olyn to consistently do that) and to use her summon effect over and over with all the bounce spells the deck has. In the best case you can reduce Endra's cost before you draw her (with Youth or Musket) because that makes replaying her way easier, but you can still go for it without cost reduction if you have to. You use Endra to clear units when you have to (especially the first few spells because you usually have to catch up on tempo when you start playing your Endras), but if you can, you go face (always try to do the math in your head: How much Endras can your hand currently play? How much damage is that? How could I best split the damage to kill really threatening units? How fast is my opponent killing me?). Sometimes you can even force Endra's mastery through, especially if you have the bounce spells that also buff her or if you use Rujin's Choice for double damage.
Lastly, some things to be wary of:
The deck has some hard counters, some of which it can answer consistently, while some others are tough to beat. The 2 biggest offenders are
Grand Suppressor and
Deans' Chamber. Both of them completely negate Endra, so you definitely have to remove them to do anything. Suppressor can be permanently killed with Torch or the market Kairo's Choice/Salvo + Salvo/Salvo + Musket, but you can also temporarily disable him with Lost in Thought or Pause for Reflection, which can sometimes be enough. Chamber is more difficult to remove, but you do have a market copy of Slag and the option to temporarily remove it with Pause.
Next up are
Tocas, Waystone Harvester and
Combrei Lawmage. Both of these heavily hinder Endra, but they don't negate her completely. Against both you have the temporary removal options again and Tocas dies to any damage combination (double Salvo, Salvo + Choice/Musket, even Torch + Endra), while Lawmage dies to a single Torch, but prevents all damage combinations except for Salvo + Musket, Endra + Musket or Salvo on their turn into Choice on yours.
The third big counter is void hate: You don't care about voidbound effects like Gavel at all, but devour effects or
Eavesdrop can be rough. Against devour you can try to just stack your hand until you can go for a big push to not play your Songs into their devour effects, but sometimes you can't wait that long and just have to risk it. Eavesdrop is even more difficult to play around because you also need to discard 2 cards, but it's rarely played at this point and if your opponent is on a slower deck you can just keep some low value cards in hand to discard.
And lastly you have to keep in mind that you dont get the power from Shavka's Song if you don't deal the damage, which means aegis, invulnerability from damage or fast speed ways to remove the unit you targeted make your combo harder (although not impossible, unless the opponent has a ton of it, like Hooru Kira tends to do).