So, some folks say that Rift is a WoW clone. I'm not sure how a fantasy mmo can not be compared to WoW or EQ or any of the other fantasy mmos. But one thing Rift has that's different is it's namesake: rifts. These unplanned events always seem to pop up where you don't want them to. And they have a big brother: invasions. These take over whole zones. If you partake in the defense of a zone, you might be still doing it 2 hours later.
This is an elite boss from a life planar invasion on the Guardian side. We downed all three bosses and still got overrun. This particular fight took place in the courtyard of the magic academy at Argent Grove.
Each of those green glowing columns are where either rifts are forming or where scouts from the life plane have put a foothold idol down and are now summoning their troops though. On the mini-map each green "X" is a band of invaders.
And here's boss #2. You can see on the mini-map where the 3rd boss is, they're marked with the skull over the crossed axes.