How often do major boss events appear?

[Lilly32]

I was able to find the one up in Human starting zone in the swamp. It was a lot of fun and at least 100 people were there. Also the loot was nice got 8 blues and 2 greens. But when do you know these things are happening? It seems like these guys are going to be a great source of loot but how do you know to get to one? I just ran into this one because I was finishing up my last heart in the area and saw the boss with a red ring around him instead of the normal orange ring. Can you see these guys from the main map if you are in a different zone or do they only show up if you are in the zone? It would kind of suck if they were so hit or miss because it was a blast and obviously not faceroll cause I rezzed quite a few people. Are they on a timer or is it either be in the zone when it starts or you are SoL?

[Larynx]

Major boss battle?

Um, there's at least one meta event per zone, which occasionally end in an elite event (Shatterer, Shadow Behemoth...). There's probably dozens of champion events and spawns per zone though.

Meta events are these long DE chains, which eventually climax in the ultimate success (or failure) state. That climax will sometimes be that major boss battle. Other times, it will be something like the Dredge meta event in Diessa, without an end boss. Meta events I don't know how to trigger. I believe they begin randomly or at certain times after it was last completed.

[Lilly32]

Yea Shadow Behemoth was the one I did. Events like him. So you just have to be there at the right place and time then? Cause I only saw that event once all weekend and I played a lot.