Exploring new decks that come into formats is an important part of Magic. Understanding new strategies, how they work and why they are strong in the metagame is important to retain an understanding of the format as a whole. Caleb Durward won SCG Open Milwaukee with a total homebrew and newcomer to Modern, Bant Spirits.
The idea is sound - put pressure on your opponent with flyers and permission. Meanwhile, play hexproof creatures to narrow down the interaction your opponent can have while putting them on the back foot, making all your cards more effective.
We've seen aggressive Collected Company strategies such as Naya Zoo have moderate Modern success in the past. Durward's deck is certainly an aggro deck, however, the spirit shell provides inherent interaction in the form of permission in addition to protection through various hexproof creatures and tricks that a typical beatdown deck can't provide. Bant Spirits is very good at maintaining a lead, and can put opponents in incredibly tough spots, so much so that it reminds me of Splinter Twin. Opponents can play around a certain card only to get punished when you actually are holding something else. I like these types of strategies since often times it not only leads your opponents into making mistakes, but puts them in situations where there is no correct play, resulting in forced suboptimal plays.
Through playing a few leagues with the deck, I certainly liked the feel of this deck. However, I did not seem to be doing particularly well, so I thought about some changes to make to the deck. The first thing I noticed was Company wasn't nearly as good as you would Anticipate. Part of the issue is while you have 29 creatures, many of them are marginally impactful one or two-drops. Without a card like Reflector Mage, your Collected Companies don't always interact in ways that allow you to play catch up. Essentially, when behind they don't help you pull back into it, and when ahead they are unnecessary. I think they are certainly good enough to keep in the list as they are insane during a relatively even game, but it got me thinking that maybe the deck could or needed to be moved into another direction.
The two-drops are good, but none of them are defensive and not very powerful compared to the what people are generally doing in Modern. While the best part of the deck is that all your creatures have flying, essentially making you an unblockable Zoo deck, the worst part is your deck is just full of Goblin Pikers in a Death Shadow's world. Steel of the Godhead impressed me much more than I thought it would. In matchups where they aren't attacking your life total, it was still really effective to make a Geist of Saint Traft unblockable, and the life gain was impossible to race while the "combo" is more or less impossible to interact with.
The first thing I thought I might as well try if we were a dedicated Spirits deck is the long-lost Standard Powerhouse, Tallowisp. If Steel of the Godhead was good, and I was looking for a huge advantage for my tribal deck filled to the brim with Spirits, it had to be worth a shot.
The problem was fitting enough enchantments into a deck that was also constrained with a high creature count to allow us to play Collected Company. To do so I had to cut the Path to Exile, which admittedly could be a huge mistake. I decided to cut a land as well just to try to fit everything into one deck. Finding the balance between how many bad enchantments you want to play is key. You want enough that lets an active Tallowisp take over the game, but not so many that you have tons of awful cards in your deck.
Now, I'm not sure if this is the most competitive deck in Modern, but I will say after going 4-1 in the two Leagues I played in, it's certainly at the very least better than it looks. Here's my list:
This list is certainly much different from the original winning list, but I feel it has a few things going for it. The card advantage and Staying Power that Tallowisp provides is rather huge. Unfortunately, the deck as a whole is a bit more clunky and can have some rather bad openers that include the enchantments. Guard Duty is awful, I would likely cut it for another Geist of Saint Traft. For this list in particular, I would try to fit back the 22nd land, which could be a utility land such has Moorland Haunt or Gavony Township.
Being completely honest here, it's likely not the best idea to play this version at a serious tournament. That being said, you still provide all the play that the non-Tallowisp version provides. You have a decent amount of interaction, and can beat many decks on the basis of overloading them with flyers. Still, Tallowisp has performed better for me, though it has been a relatively small sample. I would recommend playing with both if you are interested in Bant Spirits.