Commander Legends is the newest supplemental set to enter Legacy, and it has fewer cards than expected to impact the format. For The EPIC Storm, the two most impactful cards are both one-sided lock pieces: [[Hullbreacher]] and [[Opposition Agent]].
Creature – Merfolk Pirate
If an opponent would draw a card except the first one they draw in each of their draw steps, instead you create a Treasure token. (It’s an artifact with “, Sacrifice this artifact: Add one mana of any color.”)
Creature – Human Rouge
While an opponent is searching their library, they exile each card they find. You may play those cards for as long as they remain exiled, and you may spend mana as though it were mana of any color to cast them.
[[Hullbreacher]] is the most impactful card to Legacy from Commander Legends. As the latest iteration of effects that prevent players from drawing cards, it has powerful nuances. Unlike [[Narset, Parter of Veils]] or [[Leovold, Emissary of Trest]], it prevents opponents from drawing cards outside of their draw step. This means that resolving something like an [[Echo of Eons]] with a [[Hullbreacher]] in play will not give the opponent a single card. The other major upside of [[Hullbreacher]] is that it does not just prevent draws, but it also gives its controller a benefit when the replacement effect occurs. Instead of being able to use [[Ponder]] or [[Preordain]] as just library manipulation, these cards will give the opponent treasure tokens. Compared to existing similar effects, [[Hullbreacher]] has the most powerful version of the effect. While other cards may have other upsides, such as being sources of card advantage, being able to cast [[Hullbreacher]] in response to a cantrip to gain a mana advantage will be enough of an upside to push it to the front of the format.
[[Hullbreacher]] is most likely to show up in two places: slow controlling blue decks such as Snow Control and Urza Stompy. Urza Stompy will look to exploit the interaction between [[Hullbreacher]] and [[Echo of Eons]], similar to how it is already exploiting [[Narset, Parter of Veils]] and [[Echo of Eons]]. In Snow, I would expect to maybe see it in the main deck and one or two copies in the sideboard.
For The EPIC Storm, the existence of [[Hullbreacher]] makes the sideboard engines worse. Both [[Echo of Eons]] and [[Peer into the Abyss]] do not work while a [[Hullbreacher]] is in play. If [[Hullbreacher]] becomes a staple of the format in many decks, [[Peer into the Abyss]] might be cut for an [[Infernal Tutor]] in order to find [[Ad Nauseam]] out of the sideboard. If [[Hullbreacher]] becomes one of the most played cards in the format, more removal spells will have to be added. What these removal spells are is not entirely clear. [[Pyroblast]], [[Lightning Bolt]], and more copies of [[Abrupt Decay]] all have their appeals. [[Pyroblast]] can counter [[Hullbreacher]] on the stack and has applications against [[Mindbreak Trap]]. [[Lightning Bolt]] can remove [[Thalia, Guardian of Thraben]], [[Collector Ouphe]], and in some cases [[Karn, the Great Creator]]. [[Abrupt Decay]] is two mana, but has the upside of not being able to be countered. Depending on where the bulk of [[Hullbreacher]] sees play, adapting the sideboard to beat it should be do able.
[[Opposition Agent]] is another lock piece similar to [[Ashiok, Dream Render]]. Like [[Hullbreacher]], having flash is a significant upgrade to the effect. Unlike [[Hullbreacher]], [[Opposition Agent]] does not have a natural home. While it may see fringe sideboard play, especially if [[Doomsday]] sees high amounts of metagame share, I would not expect this to become a commonly played card in the format. Most decks do not play many tutors beyond fetch lands and a three mana spell where its floor is that it shuts down fetch lands is not a Legacy power level effect. The dream of hitting an [[Infernal Tutor]] or a [[Wishclaw Talisman]] activation with this card is the ceiling of its power level, but that will not happen often enough to push this card into many deck lists.
In the event that this card becomes widely played, it would most likely be as a sideboard card in blue decks. To combat that, the sideboard would most likely shift towards having more copies of [[Abrupt Decay]], or just accepting that the sideboard can not be prepared for everything.
Wheel of Misfortune
[[Wheel of Misfortune]] has the misfortune of a card that at first reads exciting and then it gets worse on each reread. This card would be playable and worth testing if there was a way to guarantee the wheel effect. The main issue is if both players pick the same number, neither player will draw any cards. Generally, the player with more life will be able to dictate the result of the [[Wheel of Misfortune]]. Each player can “wager” an amount of life equal to their current life total minus one. The player with the higher life total can guarantee that they will draw the cards by virtue of being able to pay more life. From the perspective of The EPIC Storm, it is rare that our life total will be higher than an opponent’s because they are generally going to be attacking with creatures and thus will have the higher life total. This card is wildly uncontrollable and is not worth testing due to the high risk and relatively low reward. A fixed [[Wheel of Fortune]] this card is not.
Commander Legends adds some interesting cards to the format and I am excited to see how they will affect the landscape of Legacy!