I’m always excited about a good board sweeper, and particularly if it falls in the Witherbloom colors! Culling Ritual has three interesting things going for it. The first is destroying noncreature permanents, the second is destroying based on mana value and the third is paying you back some of your mana investment. Let’s look at some good ways to use this card.
Culling Ritual is what I would call a “conditional” board sweeper in that it doesn’t destroy all creatures. This can be both a weakness and a strength. On the one hand, if you’re facing an overwhelming disadvantage on the battlefield, it may not save you. Alternatively, you can design your deck in a way where Culling Ritual does more damage to your opponents than to yourself. Wiping their board while leaving behind your Elder Gargaroth or Lisette, Dean of the Root can be devastating.
Giving back some mana makes Culling Ritual quite powerful, and can allow you to set up some big comebacks. It becomes an easy decision to sandbag your two-drop creature when you know that on turn four you can sweep the board and then deploy it with your extra mana. Alternatively, Culling Ritual can clean up the chaff and then give you the mana you need to Flunk their one remaining threat.
In most situations, I’d expect Culling Ritual to give you a couple of mana from destroying opposing permanents, but note that it does count your own permanents as well. This can mean a slight emotional discount on blowing up one of your own things. Alternatively, it might be possible to intentionally take advantage of that using tokens or cheap, disposable permanents. Imagine you have a Tireless Tracker and a bunch of Clue tokens. It might stink that Culling Ritual destroys your Clues. But it also might be a way to hammer home an advantage by sweeping the board, leaving behind your Tracker and generating enough mana to deploy another threat.
The reason I mention Tireless Tracker is that I’m particularly excited to play with Culling Ritual in older formats like Modern and Pioneer. It can still be useful in Standard, but Standard decks tend to have wider mana curves. In older formats, things are pressed so much towards efficiency creature decks are usually centered around one-drops and two-drops. In Modern, Culling Ritual also destroys Aether Vial, which greatly reduces the opponent’s ability to rebuild afterwards.
I envision Culling Ritual alongside cards like Tireless Tracker, Courser of Kruphix, Liliana of the Veil, Liliana, the Last Hope and Nissa, Who Shakes the World. But that’s just me! Maybe this card has even more potential in a combo-style deck where you’re taking advantage of the mana generation. How would you use it?