The first image is a concept drawing of an unnamed creature. How this demon will be attacking you is up to your imagination for now.
Official Blizzard Quote:
"While this ... thing resembles the Khazra, its form is twisted and distorted. It would only be one of many instances where the denizens of Sanctuary have been risen or reformed for demonic purposes."
The second picture is a screenshot from the King Leoric Torture Chambers dungeon that we've seen previously, of the Witch Doctor using his http://diablowiki.com/Firebats" class="wiki-link">http://media-diablofans.cursecdn.com/attachments/16/736/wiki2.gif" alt="DiabloWiki.com - Firebats"/> Firebats skill. You can also see one of the Zombie Dogs aiding in the Witch Doctor's fight against the demons. Notice the giant axe-type apparatuses that swing down damaging anyone in its path.
Click the images to bask in the glory of the high resolution versions that you likely won't see anywhere else! 25,000 more likes to go until the 900k mark where we can get some more images, and 5 more milestones until we hit the 1 million 'Like' goal. Go visit facebook.com/Diablo and 'Like' the page to speed the war effort!
http://www.youtube.com/thechatgem
I can probably find an older photo though with the skill being used.
EDIT:
Our own wiki has an older img
http://www.diablowiki.com/Firebats
Thanks a bunch man!
That is a great question. I'll have to ask. I know that Corpse Spiders is just a zombie that bursts out of the ground and spews spiders out. So that's not really a tag-a-long pet. But the others I'm not sure about.
So you're gonna be a monk?
No, you are not. I find these updates for the most part tedious and condescending*. Like I said above, this particular piece of concept art is cool (even though it could have easily been drawn by a depressed goth kid sitting forlorn in the back of his high school home economics class). But the only value I typically find in these digital deer-droppings is the opportunity to talk shit.
*diablofans is doing an amazing job, I'm directing my snark purely at Blizzard.