Besides being part of a new cycle of Curses, which were thought to be an Innistrad-only type, the most noteworthy thing about Curse of Chaos is its flavor text, featuring a quotation from someone we've never heard of before:
"Let them beg for mercy. Apart from me, no one can hear." - Siglind the Conqueror
Siglind (which can be derived from something like "victory-winding" or "steady in triumph" from Old Norse) the Conqueror is an entirely new character to the lore. Apart from that name and the fact that she has a tendency to say things like that, we have no idea about who or what she could be. Now, Siglind is a Germanic or Scandinavian female name, and as such, is a perfectly good name for an Innistradi woman. But, oddly, Curse of Inertia and Curse of Predation both have quotations as their flavor text... from Tezzeret and Garruk, respectively, whom we know a lot about. The suggestion seems to be that Siglind the Conqueror is in fact an unknown planeswalker.
The certainty that all the flavor texts of Commander 2013 Curses are attributed to planeswalkers is broken by Curse of the Forsaken, which quotes Seeta of Thraben, who is seemingly just a righteous and dogmatic Cleric on Innistrad, certainly not out of the ordinary. But "the Conqueror" is a slightly more memorable title than one that just denotes where the speaker is from. And Magic seems to lack for a good monored planeswalker who isn't Chandra; Koth hasn't been heard from in a long time and Tibalt got negative fan reception because of the perceived unplayability of his first card version. Or perhaps Siglind will be a black-red planeswalker, to give a little something to fans of that color combination who didn't like Sarkhan the Mad's gimmick.
Or, possibly, she may well be the black-red dual-color new legend in Commander 2013; no two-color legends from this set have been spoiled just yet, but there seems to be no reason to break from the original Commander's pattern of ten tricolor and five bicolor legends.
As far as her abilities in either version: "the Conqueror" seems to suggest gaining control of things; or perhaps it's a metaphorical reference to her conquering death and she has reanimation or flashback themes.