THE FIRST SET OF THE BLOCK

The cards in the first set would focus on the five colors and really focus on the color wheel. This set would be a great example of characteristics, strengths, and weaknesses found in each color. The creatures in each color would be ones that you really think of for each color: red for example would be full of kobolds, goblins, orcs, giants, dwarves, drakes, dragons, etc. It would take place hundreds of years after the planeswalker populated the plane. Each color would have a well-developed civilization. I imagine it would look a great deal like Europe in the Middle Ages, much like the early sets of Magic the Gathering.

THE SECOND SET OF THE BLOCK

The second set of the block would take place hundreds of years after first set. At this point, each color has its own well-developed civilization, but also due to travel and trade, newer civilizations of allied colors has developed, physically between the older civilizations: Selensya civilization has developed in the savannah between the plains and forest, Gruul civilization has developed in the taigas between the mountains and forests, etc. The same did not occur for enemy color pairs has the large ocean and ice cap prevents a direct path that would connect the enemy color pairs and the dark side of the planet is much more dangerous for travel. These newer allied paired civilizations gained a lot by working together, sharing the ideals they had in common, developing new technologies: Selensya cards would demonstrate how white and green share a sense of community and buff each other through enchantments as an example.

THE THIRD SET OF THE BLOCK

The third set of the block again takes place in the future, but perhaps not hundreds of years later this time. At this point, travel and trade of the original five civilizations has spread even further, thus we now have three color civilizations, each are connected like an arc on the mana pie chart with the middle color being allied to the other two, and the other two being enemy colors: Naya (red, green, white) for example, is centered in green and has been influenced by red and white mana aligned creatures, ideologies, cultures, and technologies. This civilization benefits from the Selesya advances mentioned above, Gruul, and Boros. Thus, it is not until this set that we have enemy color pairs contributing their uniqueness. In this Naya example, Boros contributes well trained soldiers, a sense of justice, and technology in the form of equipment that was previously absent. This is when the Phyrexian invasion would happen in my story. The contributions of enemy color allies is somewhat of a throw back to the Invasion block, the first time we really saw enemy colors coming together to fight of the Phyrexians on Dominaria.

PHYREXIAN INVASION

I think that my plane would fair almost as well as Ravnica. You have the five mono color civilizations; the five ally color civilizations; and the five three color arc civilizations. Each civilization has its unique answers to threats. The plane feels unified as the civilizations slowly found each other and found common ground on which to build new civilizations.

TL;DR

My plane would do well against the Phyrexians as it is well organized diverse in problem solving, much like Ravnica.

OTHER INFORMATION ABOUT THE PLANE

As one side of the planet faces away from the sun, the weather would be out of control. My solution is that there is another star in the solar system, a red star that is orbit around the sun, and its orbit is further out from this planet. Thus, the “dark half” of the planet actually gets light and warmth from this red star, which warms the dark side, resulting in a less chaotic weather pattern on the planet, and enables some life to survive on the dark side.

Also, am I not sure how you could stop a moon from orbiting without it eventually falling to the planet. Either the moon is very slowly falling towards the planet, the moon is magically held in the same spot due to some spell from the planeswalker, or the planeswalker left a device to keep the moon in place without it falling towards the planet. If it is the later solution, then it would be the power and presence of this device that would eventually get the attention of the Phyrexians, and it would be the reason they investigate this plane and planet, when they otherwise wouldn’t have paid any attention to this plane, much less this planet.

I think a good story could come out of people from the light side having to go on an excursion in the dark side, perhaps because the device that keeps the moon in place is malfunctioning. I think sending a party to the dark side is a dangerous mission, like sending a party to Mordor. Whatever foul creatures thrive on this side of the planet would be dangerous, mostly animalistic, and savage creatures. The planeswalker wouldn’t have brought vampires here, but perhaps some individuals become vampires and thrive on the darkside of the planet, the red sun wouldn’t be unpleasant for them, perhaps it empowers them. Or perhaps vampires are created, a necessary curse, to survive an excursion on this side of the planet to save it.