In a nutshell, they believe super-powered beings are an abomination to the natural order, so their mission is to seek out those with powers throughout the universe, and exterminate them:
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*And remember: not only do The Timeless number in the thousandS, but the tech they employ has made them a very powerful race. For example: blows from Superman/WW barely even faze them, Aquaman's Trident cannot pierce their armor, Flash's speed cannot overwhelm them, Cyborg's attempts at hacking and whatnot is completely ineffectual, etc. etc.
Not entirely sure, as very little has been revealed about her thus far. 'Molly' is obviously some sort of hyper-evolved(and seemingly immortal/ageless) being, who is intimately familiar with The Timeless and their machinations. Though she looks human, she is evidently part of a [yet unknown] alien species.
She also has access to tech that enables her to time-travel to key moments in earth's history... She is doing so to try and stop The Timeless before they alter the earth's timelines, and erase all of its super-powered beings from ever existing: (please log in to view the image)(please log in to view the image)(please log in to view the image)
*On an unrelated note: the last scan reconfirms the fact that the Speed Force was only created when Barry Allen became Flash.
I know what truly made The Timeless come to Earth: Flashes city evacuation feat. They just couldn't grasp it. "Lightspeed..lightspeed?! He has fundamentally altered reality itself to be able to accomplish that at lightspeed, we need to exterminate these f*cks before all logic ceases to be".
__________________ Chicken Boo, what's the matter with you? You don't act like the other chickens do. You wear a disguise to look like human guys, but you're not a man you're a Chicken Boo.
And it was explicitly stated that what happens to mainstream earth directly affects the whole of reality -- shapes it, breaks it, and rewrites it: (please log in to view the image)