Aftermath was an intergalactic drug dealer with a higher purpose. One out of every 200,000 druggies who tried his modified 'heroin' became a portal to the Source Wall. Aftermath planned to use these portals to obtain the whorlogog, the blueprint of the universe.
The Justice League Elite infiltrated Aftermath's organization, but could not stop him from opening the portal. Aftermath's visions of grandeur were cut short when the whorlogog (under Vera Black's inadvertent control) tore him in half.