There are bad guys and there are badder guys, but only a few are dangerous enough to threaten you personally - at least by implication. These aren't your bank robbers. They aren't revenge-driven enemies, focused on killing only one or a few superheroes as their primary goal in life. They aren't even your would-be world conquerors. They threaten the lives of everyone and everything in the universe, or they threaten the universe itself, or they threaten a whole bunch of universes. And they do it pretty much every time they draw a breath. When any of these beings cracks a smile, you know that s*** just got serious, and you'd better run as far and fast as you can, preferably to someplace behind the army of superheroes that'll be flying out to stop them. Ranking beings of such incredible power can be a little challenging, for the same reason it's hard to tell which skyscraper is taller when you're looking at them from the ground floor. It's tough to even conceive of the power that some of them channel, much less fathom it. Let's all hope that if two or more of them show up in a story together, they spend most of their time beating the crap out of each other instead of our heroes because I don't like the universe's survival odds otherwise. And comics have broken universes so often, you have to be concerned about how many we have left.