Later today, I will post the last pack of the pack per day challenge. I haven’t been able to post much, but I can today.
Rise of the Eldrazi, although it hasn’t been officially announced, is the name of the spring set for 2010. It will be a large (Zendikar size, not Worldwake size) set that will be drafted by itself. (RRR, not ZWR) It will be set in Zendikar, but will be completely different. That means that there probably won’t be allies, traps, landfall, or kicker. (They will exist in Worldwake)
Prerelease: April 17-18, 2010
Release: April 23-25, 2010

Here’s the logo:

And here we see Sorin Markov and Nissa Reveane in front of something huge, which I’m assuming is the eldrazi:

Now on to Marit Lage. Whether or not Dark Depths is in Rise of the Eldrazi (I doubt that because the Eldrazi would have been free by then, and also Marit Lage was trapped in ice on a different plane.) there is a lot of evidence that Marit Lage is an Eldrazi. Let’s start the way we were able to figure out that Nicol Bolas would be in Conflux: We’ll look at a Zendikar card for comparison.

Now, there are a few things to compare this to. First, we’ll look at Dark Depths itself:

Compare this to the eldrazi monument and to the ROTE image. Looks similar, right? Even before looking at it, Eldrazi Monument makes creatures bigger, flying, and indestructible. Marit Lage is big, flying, and indestructible. Look at the Marit Lage token:

Compare that to the eldrazi. If you still aren’t convinced, look at the Ice Age card Wrath of Marit Lage and compare the flavor text to that of the Eldrazi Monument:

Dread Marit Lage lies dreaming, not dead. That’s the flavor text here, while on Eldrazi Monument the flavor text is: Gods don’t die. They Merely Slumber.
Now, the story line evidence. Marit Lage is very old, and isn’t a planewalker. Marit Lage can travel through the planes, in a different way. Here’s a link to the amazon.com book description of the Zendikar book, In the Teeth of Akoum. To quote the review:
For gamers and fantasy fans alike, a fast-paced, stand-alone adventure that brings the popular trading card game Magic: the Gathering® to life.
Lurking in the space between the aether and the physical plane, there is a great evil waiting to emerge.
Zendikar is a land of danger and adventure, a world of deadly risks and priceless rewards. It is also a prison to one of the most deadly species known to the Multiverse: the dreaded Eldrazi.
When our story opens, part of the mystical containment spell that has kept the Eldrazi captive for millennia has been breached. The brood lineage, the Eldrazi minions, have been released and are poring over the plane, devouring everything in their path, but the swath they cut across the land is nothing next to the destruction that the still-imprisoned Eldrazi Titans will wreck once released.
Nissa Revane, a planeswalker and proud elf warrior of the Jorga Nation, is witness to what the brood lineage can do. She sees that they pose a bigger problem than most suppose. Sorin, an ancient vampire planeswalker, knows this as well as anyone because he was among the original jailers of the ancient scourge. He has returned to Zendikar to make sure the Titans do not escape. They both want the Eldarzi threat extinguished but each has their own agenda. Nissa wants the Eldrazi off her plane entirely. Sorin wants to put the lock back on their cell. And there are still others who want the Titans to escape.
Together they set out across the land on search of the Eye of Ugin, the source of the Eldrazi uprising, where they will face what could be their final challenge. Will the Eldrazi escape to menace the Multiverse once again?
While we’re at it, look at Ghostfire, from Futuresight, and look at the flavor text:

Back to Marit Lage. The text shows that Marit Lage has the same characteristics that the Eldrazi do. They were ancient, hugely powerful beings that were trapped on Zendikar. Is it possible that one was trapped in ice on a different plane instead? I think the answer is yes.
I also want to make one more point. Because of Vampire Hexmage, Dark Depths has been thrown into actual use in tournaments. Was that intentional? (Actually, I don’t think that was intentional. But I think the rest was.)