User blog comment:Rassilon of Old/Silhouetted characters on the Young Justice: Invasion poster revealed!/@comment-65.96.106.145-20120519023713

The hooded character next to robin is Secret, from the episode secrets. It fits because secret was a founding member of the young justice team in the comics and a best friend of wonder girls. Plus as far as I can see, theres no space between the hooded figures legs, like there would be if they were wearing pants, which means the person is likely wearin either a dress or a cloak, like the cloak that secret wears. I dont know about you guys but for me the evidence points to secret.