As Doug said: "They tend to represent white’s harsher aspects: its rigid sense of justice, its ferocious defense of ordered society, its ruthless punishment of those who defy the law."
They would make for some amazing white antagonists, but they were always pushed on the sides because of how popular angels are and you can't have too many big white flying creatures in one set. Now, it appears as if angels will be absent from Theros and will be replaced by the archons.
With the guide referring to them as "monsters" and with this Agnomakhos fellow being a tyrant, it's good to finally see monowhite "evil" creatures.
I'm really eager for the next part, if only to know more about those archons.
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Several of the revealed cards so far have been suggestive of the beginning stages of an Eldrazi invasion, particularly since mutated eyeballs and weird fleshy growths and tentacles, for example, would be the sort of thing you'd expect from Emrakul, the corrupter of biological life. Though this trait was only established of Emrakul recently, while she was absent from Zendikar.
The story, as well as several representations of Avacyn so far, with the presence of black in her eyes sounds quite a bit like Phyrexian ichor. In the trailer it appears she's got some black tears even.
Then, Nahiri is pissed off and doing weird lithomancy stuff. Tamiyo's got notes on the Moon being weird and its connection to the sea.
Those are all plausible and perhaps related causes. Though the Chain Veil is also possible. Perhaps Garruk was in the forest when Avacyn rescued the kid, corrupting her in some way. If the strength of the curse was so strong that it overwhelmed the Cursemute, that would explain it failing for werewolves. Enchantment on enchantment action like that is a bit easier to understand than it happening as a result of Phyrexian corruption, by comparison, though Avacyn could have simply rescinded her magic.
As for Nicol Bolas: sweet Jesus, I hope not. This is the least interesting option. Please no.
So there are some serious possibilities, or really, permutations of all the different clues we have so far. As is proper for a mystery block.
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