The Legion by Dan Abnett and Andy Lanning Vol. 1

Upon infiltrating the United Planets' means of hyper-accelerated interstellar transportation, the Blight entwine Earth and destroy its forces within hours. Where life once flourished, it now deteriorates. And those who don't die meet a worse fate: they become of the Blight. That includes the Legion of Super-Heroes, the U.P.'s young champions. Unable to fend off the invaders, their once-great numbers now serve the Blight and hunt down the last resisting Legionnaires--the ones looking to find enough survivors and open one last Stargate to freedom. Earth, the United Planets, the Legion of Super-Heroes...they're all damned.