So it seems that the Vex are one of the fan favorites, but the amount of hype these guys get is ridiculous sometimes. In the grand scheme of things they're irrelevant and will never be a threat on the same level as the Hive, the Worms, or the Darkness itself. To understand why we need to start by looking at the biggest difference between our universe and the one in Destiny. Within our universe existence is governed by physics. Within Destiny's physic is only one of three governing forces, the other two being Darkness and Light. Yes, Darkness and Light aren't only philosophies and entities, but fundamental powers by which existence itself is governed. Now, I know what you're thinking "but Saint, the Vex have time travel cant they just *insert timetravel nonsense here*?" No, they clearly cant or else they'd have won long ago. One thing we all must realize is that the Vex deal far less in timetravel and far more in alternate timelines. They tend to jump between roughly congruent moments in parallel timelines rather than truly draw from the far future or distant past. In fact, the only time we do see them do that are in the Black Garden and the Vault of Glass, two very unique instances that are, from what we can tell, not representative of the whole. Now, this isn't to say they aren't powerful in their own right. They have an understanding of physics and a mastery of space-time that we cant even begin to imagine. The problem is they're incapable of comprehending either Light or Darkness, as well as anything sufficiently close to either of them. The Vex work by collecting every possible variable, simulating every scenario imaginable, and then taking steps to ensure every scenario ends at the very least in their survival. For something like that, the inability to comprehend, and by extension simulate the Traveler, the Darkness, the Guardians, Oryx, the Taken, and the Worms, that's a pretty massive handicap. They can't use their greatest weapon because its useless in this massive ideological war they've found themselves caught up. [b]tl;dr:[/b] Three people are playing a game of Texas Hold'em. The first two guys play normally and follow the rules. The third guy is only allowed to play with the 2 cards he's initially dealt. He isn't allowed to play the flop, turn, or river, but the other two guys are. The Vex are the third guy in this scenario playing against the Light and Darkness.