The Infinite Dragonflight

Okay.

I think it is safe to infer that the Infinite Dragonflight was created by the Old Gods and they are part of their plan to escape, in some form or another. They are almost certainly corrupted bronze dragons.

What do we know?

1) The Old Gods have been trying to bust out of Azeroth since at least the War of the Ancients. They got Deathwing to create the Demon Soul, and manipulated things so that it fell in to Malfurion Stormrage's hands, blowing up the portal and eventually the world in the Sundering. Azshara also created the Naga (herself included) in a pact with the Old God.
2) The Old Gods have been constantly manipulating events to get things that they want. Some people theorize that Deathwing was the real conspirator behind the destruction of Draenor, as a test run for the Cataclysm, which is supposed to do what the Sundering didn't do. They are always driving people mad.
3) The Old God C'Thun made war with the Brood of Nozdormu in both Wars of the Shifting Sands, along with the night elves in the first and the rest of Azeroth in the second.
4) Even the bronze dragonflight does not know the origins of infinite dragonflight or what their purpose is.

Now the infinite dragonflight has no clear explanation of their origin, but we get some hints.

In Wrath of the Lich King, Chromie, Ambassador of the Bronze Dragonflight, sends players on a quest to take a powerful artifact to the Bronze Dragonshrine in order to divine the true identity of the leader of the Infinite Dragonflight. Instead of the leader being revealed, players reveal Nozdormu himself. While this is shrugged off as merely being interesting by Chromie, it blatantly suggests that Nozdormu himself is responsible for the Infinite Dragonflight.

It is unknown at this time whether Norzdormu is the leader, and it is also unknown what, if anything, would lead him to this fate. Why would an Aspect suddenly go from carefully guarding the events and happenings of time, to trying to disrupt them? Why, he’d have to be…mad.
(shades of grey)

Finally, we know that Nozdormu is away on some kind of quest and that's why we don't see him in the Caverns of Time. In the War of the Ancients trilogy, Krasus tells us that Nozdormu knows how he will meet his demise, and he check out what he says to Krasus in Day of the Dragon:

Nozdormu knows he's going to do something bad. Perhaps he will be corrupted like Neltharion and do some crazy stuff like disrupt timelines. We also know that you have to save a bronze dragon from the Infinite Corruptor in order to get your bronze drake mount.

Where have we seen them show up?

Now. Let all of that marinate in your brain for a moment and consider when players have to intervene to stop the Infinite Dragonflight from altering the flow of time.

• Escape from Durnholde. They are attempting to stop Thrall from escaping his internment camp.
• Opening of the Dark Portal. The infinite are trying to stop Medivh from opening the Dark Portal, allowing the Orcish Horde to enter Azeroth and begin the First War.
• Culling of Stratholme. Interfering with a turning point in Arthas's journey to Northrend to become the Lich King.

Why would the Old Gods want to interfere with each of these events? Think about their results. Thrall escapes from Durnholde, and later becomes the leader of the New Horde. The New Horde which arose out of the ashes of the Orcish Horde. The Orcish Horde came to Azeroth through the Dark Portal. This is the same New Horde that was heavily involved in the second War of the Shifting Sands, which vanquished C'thun. C'thun who was imprisoned by the Bronze Dragonflight. Coincidence? I think not.

Especially when you consider the repeated references to some specific plan, or to a master, or to ensuing choas, which the Old Gods love.

Aeonus in Opening of the Dark Portal:

• The time has come to shatter this clockwork universe forever! Let us no longer be slaves of the hourglass! I warn you: those who do not embrace the greater path shall become victims of its passing! (It is worth noting that this quote was partially stolen from Medivh...)
• No one can stop us! No one!
• One less obstacle in our way!
• We will triumph.. It is only a matter...of time.

Temporus, in Opening of the Dark Portal:

• My death means ... little.

Chrono Lord Deja, in Opening of the Dark Portal:

• Time ... is on our side.

Epoch Hunter, in Escape from Durnholde:

• Ah, there you are. I had hoped to accomplish this with a bit of subtlety, but I suppose direct confrontation was inevitable. Your future, Thrall, must not come to pass and so...you and your troublesome friends must die!
• Thrall will remain a slave. Taretha will die. You have failed.
• No!...The master... will not... be pleased.

Infinite Corruptor

• How dare you interfere with our work here!
• My work here is finished.

And the Culling of Stratholme. Why would the Old Gods want to thwart Arthas? Easy. Stratholme was a turning point for Arthas on his road to becoming the new Lich King. Remember that the old Lich King was drawing him there because the power of the Frozen Throne was severely waning. The infinite dragonflight simply attempts to kill him, rather than turn him from his path. So with Arthas dead, and the old one's power waning, the Scourge may be defeated much more easily as time goes on. There is no new Scourge invasion to draw the combined military might of Azeroth to Northrend on a counteroffensive. Why is this important? No one discovers the Secrets of Ulduar.

And even if they did, only the Alliance would be able to do anything about it, seeing as how the Infinites would have tripped up the New Horde's formation.

What does this mean?

This is interesting for several reasons:

Old God Synergy

It implies that the OGs are working together, at least in some minimal capacity. Previously we had not heard of this. C'thun was the problem of the Bronzes, yet by killing Arthas, you are aiding Yogg-Saron. Perhaps they work together, perhaps they do not. It seems reasonable for them to understand situations where what is good for one of them is also good for all of them. If no one discovers the Secrets of Ulduar, no one kills Yogg. More Old Gods executing sinister plans to divide and menace the mortals of Azeroth is better than less. Once they regain control, who knows who friendly they will be to each other.

Thrall is a threat.

There is a strong interest in Thrall. This may not mean anything in terms of the way the Infinite see things, but for us, notice that they tried to stop the Dark Portal only after we saw Thrall to safety. Failing at that point, they had to go earlier. They would like to avoid altering the timeline too much to avoid unexpected results, so they play as conservative as they can.

This confirms (if this theory is correct) that Thrall is going to be a major figure in the defense of Azeroth against the Old Gods, as was recently discussed at Blizzcon.

Thrall is one of the few orcs out there who have blue eyes -- a sign of great destiny, much as golden eyes and antlers signify the same among night elves. It's been assumed all these years that Thrall's destiny lay in leading the Horde ... but what if that's not actually the case at all? What if Thrall is part of something much, much larger than this? In response to a question regarding whether or not we would be taking out some of the other dragon Aspects in the same way we took out Malygos, Metzen responded that future patches would introduce story development in which the dragon family would have to get involved, that there would be a big battle, and that "they [the Aspects] will perform the function for which they were created." The specific question posed was "How will the [dragon] family and Thrall pull this [Deathwing's defeat] off?"

Then Metzen gave us another seriously interesting hook. He asked, "What aspect is missing from the family?" After some silence, he responded with Deathwing, the Earth Aspect. Earth -- and the family of Aspects is broken and has been broken ever since Deathwing's betrayal during the Sundering. The implication here is that someone needs to step up and take the place of the Earth Warder ... and who better to do this than a shaman who is possibly more powerful than any living creature on Azeroth? Or as Metzen put it, "Perhaps that's a way our boy Thrall can distinguish himself, down the line, in helping to bring the family back together for the big win."

Thrall is also currently in Draenor learning to fix the broken elements. They got broken thanks to the efforts of Deathwing, according to a fairly sound theory I've run across. Even if it isn't true, now Deathwing is trying to do something similar here on Azeroth, and what Thrall is learning from what happened to Draenor's shattering will help him fix Azeroth. The inference here is clear. Thrall is a problem they tried to fix in the Caverns of Time twice. That means they couldn't defeat him in the future. Thrall, I guess, has not nearly exhausted his badass potential.

War of the Ancients Planned CoT instance

The Old Gods were responsible for the Demon Soul, which destroyed the portal summoning Sargeras, causing the Sundering. The Old Gods wanted to escape their prisons beneath the Earth, yet only C'thun seems to have been able to do it. That says to me the Sundering didn't quite go the way they planned. Or maybe they wanted the Demon Soul to be used for something else. We don't know. It may be like Mount Hyjal, where we don't even see the Infinite Dragonflight. But I wouldn't bet on that.

Nozdormu

With this guy we get some interesting stuff. He knows he's going to be a problem for the other dragons later in life. He also cannot avoid this. But he also knows. Perhaps that gift/curse of knowledge means that he will be able to act in some way, some sacrificial way, to prevent the looming crises. Especially because Chris Metzen said it was badass. And as we all know, everything badass in time travel involves knowledge of the future and going back in time to influence things in the future that prevent/cause your own death. And I don't know if he has fallen victim to the Old God whispers, but Neltharion did, and some speculate that Malygos did too, thanks to Yogg, after he regained his sanity. But maybe the Infinite Dragonflight has some hidden purpose we're unware of.