Strixhaven will deliver us (at least) 10 Deans, spread across five double-faced cards. For Witherbloom, we get Valentin, Dean of the Vein and Lisette, Dean of the Root.
When it comes to evaluating double-faced cards, you don’t need to fret if both sides aren’t created equal. This isn’t to bash either Valentin or Lisette, as both creatures seem useful and pretty efficient for their mana value. What I mean is, you don’t need to construct a deck that’s equally interested in casting Valentin on turn one or Lisette on turn four. Even if you think you’re going to want Lisette most of the time, there’s still value in having the alternate side for games where you’re light on mana, where you already have a copy of the desired legend on the battlefield or any other reason why the situation might call for it.
In an even more extreme case, you can play these double-faced cards in decks that can only cast one of the sides – like mono-green or mono-black (splashing off Triomes or Pathways can even give you some extra value).
Of the two, I think the Dean of the Root has more in-your-face power level. In particular, she’s an incredible pairing with Scavenging Ooze. I’d expect a reasonable board of creatures involving Lisette and Ooze to often one-shot the opponent if there are two or more creatures in graveyards.
Other desirable ways to gain life include The Great Henge, Elder Gargaroth, Klothys, God of Destiny, Food tokens and lifelink creatures. One lifelink creature, of course, comes free with your purchase…
It’s nice that Lisette and Valentin play well together since, as mentioned, they’re legendary. You can have one copy of each on the battlefield, but you can’t have two copies of either one.
Midrange decks aren’t often interested in one mana 1/1s, since they tend to be a little bit low impact. However, Valentin could be at home in a lower-curve beatdown deck or even Vampire tribal. Notably, you can play Valentin // Lisette in a deck with Lurrus of the Dream-Den as a companion.
There are a couple of nice subtleties to this card. One is that he triggers upon creatures dying to both removal spells and combat damage. Another is that even when you don’t have mana to spare, the opposing creature will still be exiled. This can be a major headache for certain strategies like Standard Rogues and Rakdos or graveyard-centric decks in older formats. In this way, Valentin is like a mini version of Kalitas, Traitor of Ghet.
I predict I’ll be using Lisette, Dean of the Root a lot, since I’m a Witherbloom mage to my core, and since most of the decks I build feature Scavenging Ooze and The Great Henge anyway! Which Dean are you most excited about?