I think I've settled on at least a few themes for different factions, apart from the original idea that each color would have a primary attribute that would be powerful.
Emptiness, being the color of Endurance, will also have protection as a major theme. In this way, they might be better defensively all around, such as having some bonuses to their attributes on defense. They will also be Rogation-heavy, where advantages and bonuses can be had by playing Rogations, or some cards might allow you to draw Rogations.
Thanks to Papaya-Style for the new art on Naomi:
|Click to enlarge.|
I'm also considering Emptiness having a “lone wolf” mechanic, which would encourage Emptiness to frequently have only one Crusader at a time out on the Field. Naomi is the type of card, for instance, the punishes the player for having too many Crusaders on the Field, but is otherwise pretty powerful. In this instance, however, since killing isn't something Emptiness often wants to do, the detriment isn't so bad as to be unplayable; the player can have other Crusaders in the Field, but it's only a minor setback against players who are aiming to end the game by killing out Emptiness. Emptiness might have pacifistic Rogations, such as Burial Rites, Wedding, Psalms, and the like.
Solidity, being the opposite and harsh opponent of Emptiness, will gain advantages for having a fuller field state. They might also get a card-in-hand advantage with Crusaders, perhaps by having Solidity be able to draw Crusader cards, like some Crusaders that perhaps allow them to draw a Crusader upon successfully crusading. I also like the idea of Solidity being in a precarious position, however, by having traitorous cards like Earthlings and The Derelict, which offer bonuses when they are in an opponent's Field, or quick-enablers like Hitchhiker. This has the fun implication that Solidity is not as solid as they think they are.
The Infinite like to think they rely on logic and reason, so I think there may be a bit of Frenzy hate in their cards, either to negate Frenzies, prevent them from being placed, or drawn, or anything of that sort. Or perhaps they have the more explicit “does X against Devotees, does Y against Zealots” than other factions. I'm thinking they might also be the faction for players who like a more complex game, perhaps by giving them a separate token resource mechanic, or perhaps at least allows them to use normal tokens for other means, like “if this is on the Field, you may pay a token to draw a Rogation” or something of that sort.
The Noise, being the opponent of The Infinite, are more straightforward. They probably like to be Frenzied, so there will be more bonuses for Frenzied cards. They will also have clever, but simple, devious tricks, such as having Crusaders that can come down to the Field at inappropriate times, or just do chaotic stuff like Kamikaze. They may also be pro-Spiker, in that late game, their Crusaders may get bigger bonuses based on the number of Spikers already drawn, giving them a reason to get closer to the end. Perhaps they will have lots of late-game Rogations, or Crusaders that can be beefed up when seven Spikers are out.
To all that end, I've got a lot of rearranging to do with cards, abilities, and the like. I've also got to come up with a lot of interesting variations on these themes, and group them loosely in sixteen-card Crusader sets. That process has already started, so soon I'll be rearranging the Google Drive to reflect that.