It's the Magic: Phyresis (Improved!)

But if…then…hm
Elspeth’s plane was overrun by The Phyrexians. My understanding was that she wasn't from Dominaria or Phyrexia. Doesn’t that imply that Phyrexia was a threat to more than Dominaria? Was this covered during the original Phyrexian storyline? I mean, if you have two worlds (Phyrexia and Dominaria) infected by Phyrexia, and an ensuing fight in which both worlds are purged, then you figure the Phyrexian problem is ‘solved.’ Forever.

Let me go back a few steps; the first big storyline that Magic: the Gathering ever did was The Weatherlight Saga. It covered the intrepid crew (because crews are always intrepid) of the airship Weatherlight, which consisted of Gerrard, the human protagonist natural leader reluctant hero chosen one, Karn, the pacifist iron golem, and some other dudes/catladies. The Weatherlight sailed from their home plane of Dominaria (setting of most of Magic's early stories) to a few other planes (accidentally, if I'm not mistaken, adding "Jerry O'Connel" to Gerrard's description) and stumbled upon a plot by a plane called Phyrexia to invade Dominaria.

Phyrexia is a shitty place filled with flesh-hungry zombies and metal abominations seeking to "compleat" Dominaria (and everything else) by making all life on it into a Phyrexian horror (or zombie, or insect, etc..). Phyrexia invaded Dominaria and, you can say the conclusion with me here, everyone worked together, some guys did some heroic things, and a the bad guys were defeated with a Deus Ex Machina. Quite literally, Karn himself, providing some of that "Machina" ignited his spark and became one of the early setting's godlike planeswalkers. With the Phyrexians (and Phyrexia) destroyed and a few story hooks left dangling, Karn went off to make a metal plane and didn't show up again for a while.

Which is kind of, kind of a dick move.
Karn: "Hey fleshy friends, saving the world with you guys and fighting off these undead/machine monsters made me realize how much I want to go and make a place from the ground up."
Gerrard: "That's great guy, maybe I can visit sometime. It'll probably be really nice."
Karn: "No. I'm going to make it entirely out of metal."
Gerrard: "Oh."

Now, a spot of Phyrexian oil stuck in Karn (explains a lot really) has spread across Mirrodin, corrupting Karn and giving birth to a new set of Phyrexians ready to take over the metal plane and something something something dark side, something something something compleat.
Back to my central bitching; if there are multiple worlds overseen by the products of Phyrexian Oil (an interesting case of Stigler‘s Law, in that the oil isn’t apparently from Phyrexia, but is named for it anyway), then wouldn’t it follow that they, like Phyrexia, would seek to spread that infection. Was Phyrexia the only plane with the leadership necessary to build a planar portal and actually spread the infection on a greater scale? Does this imply that other worlds are overrun by Phyrexian Oil Cultures, either placidly working towards compleation or excitedly trying to find a way to work their way into the rest of the multiverse?

Given the potential for fractures in ‘Phyrexian’ society in Mirrodin Besieged (allegedly due to the availability of multiple-colored mana which wasn’t available on Phyrexia [which in turn raises more questions about Elpeth’s plane]), would it be possible that these Phyrexian Oil Cultures could even re-engage one another, with potential hostility?

Action
I’m really thinking about "Action." It's the codename for the final set of the Scars of Mirrodin block, and it will resolve the Phyrexian invasion of Mirrodin and either be called New Phyrexia or Mirrodin Pure. I’m sure whichever we get will be disappointing (you can’t really help but to disappoint my expectations, even when the fine people who create Magic have done such a great job of being utterly unafraid of giving their universe edges so messy and ambiguous that the setting is practically one half of story hook velcro.).

Either there’s going to be a card called ‘Karn, Father of Machines,’ or there’s going to be a ‘Sword of Courage and Honor,’ well, they’re going to have the sword anyway, but you know what I mean; both potential titles for the final state of Mirrodin are absolute: Mirrodin Pure or New Phyrexia. Either Mirrodin will be competely subsumed by Phyrexia or Mirrodin will be utterly cleansed of the influcence of Phyrexian Oil Cultures. It’s possible that it’s a rope-a-dope; where we’re getting told that Magic can only make one, bipolar outcome, only for it to exploit that expectation we’ve been drawn into and give us something nuanced. I mean, they could call it Monkey Basketball Chocolate and we wouldn't know until it was leaked somewhere on the internet.

Note that when I say ‘nuanced,’ I mean something less than eliminating all Phyrexian taint from Mirrodin utterly or the complete Phyrexian takeover of Mirrodin. Because of all of the work that’s gone into characterizing Phyrexia (especially considering the multi-color approach that’s introduced, but barely explored in Mirrodin Besieged), I seriously doubt they’re going to eliminate Phyrexia. No matter how Scars of Mirrodin turns out, Phyrexia’s return is as inevitable as Ben Sisko’s. Whether that’s a last-minute escape via Karn or a primitive portal or whether there’s a different Phyrexian Oil Culture to be introduced in a few years that needs the establishment set up here, Phyrexia will be back, if it leaves at all.

I’ve taken Phyrexia’s victory in Mirrodin as a given; they’re villains, they’re well-liked villains, and the theme of the past few sets has been to establish dangerous, extra-planar threats to portions of the multiverse which aren’t Dominaria (between the lines work also places Ravnica as a popular place which isn’t a source of all-consuming evil, and to sum up my thoughts on that, I’ll just nickname it Ravnic-Yavin IV or Ravnicalderann.). If Phyrexia will be back, why bother having it leave at all? Mirrodin and Phyrexia co-existing is redundant; why have an artifact plane and have an evil artifact plane? Mirrodin doesn’t bring much to the table aside from the novelty of its idea, which I feel has been fully explored in both the original Mirrodin block and in Scars of Mirrodin. It’s a familiar place whose destruction/corruption will do a good job of bringing home just how bad the New Phyrexia is.

All this fits on a story level and on a meta-level, and an admittedly subjective look at the cards backs it up. On the one hand, I see some top-tier Phyrexian shit in Mirrodin Besieged, and that’s kind of bad for Phyrexia. What’s going to go in that final block? The war-winners. The nails in the coffin. If the Phyrexians win, it’s the metaphorical Phyrexian flag waving over the metaphorical Mirran capitol. But I already see those cards for Phyrexia: Glissa the Traitor, Blightsteel Colossus, Phyrexian Juggernaut. Mirrodin has Battle Cry Guy. Battle Cry Lady. Okay, Thrun’s (the regenerating troll in a set with Infect) in there and you’ve got (the kickin’ sweet) Darksteel Plate. Mirrodin is putting up a good fight, but it seems like they have more to do while Phyrexia is peaking.

The only way this doesn’t work in Mirrodin’s favor is if you take a step back to include Scars of Mirrodin. Scars has Ezuri, Kemba, Koth, Elsbeth, Venser, Geth, Mirrodin paragons, all. While you can debate Geth with his Phyrexian watermark, this is the best of Mirrodin. These guys are the war winners for Mirrodin, and they’ve already been released. I doubt they're going to put new versions of these same characters in Mirrodin Pure to demonstrate their victory. A purified Karn would be something new to add to the Mirrodin side, he’d be just as big with a Phyrexian victory, a victory that offers color-sensitive Praetor legends that can replace their Mirran counterparts and a convenient new Phyrexia of many colors to fill out a set of its own, giving players evil in their choice of flavors.

And when you think about it, isn't that what we really want?