Thomas Grayson is an alternate-future version of the Red Hood encountered by Captain Atom after Atom absorbed the energy from Magog's modified energy lance and was thrown 112 years into the future. It could be assumed that Thomas is related to Dick Grayson, but such a relationship is not confirmed or detailed. Thomas's costume appears to be the hard-helmet worn by Jason Todd during his time as the Red Hood paired with body armor very similar to that worn by Deathstroke, but with a yellow-encircled bat logo above his left breast. He is familiar with the operation of Boom Tube technology, but otherwise his abilities are unknown.
Thomas was a member of an alternate-future Justice League of America which included the original Martian Manhunter, Power Girl, and the Creeper, as well as Damian Wayne as a new Batman, a new version of Shazam named Sahar Shaheen, a hero named Blue Scarab said to be related to the Blue Beetle, a clone of the original Plastic Man, and a new Black Canary said to be a descendant of Hawk and Dove.
Thomas Grayson was created by writer Judd Winick and drawn by Aaron Lopresti for an issue of the series Justice League: Generation Lost.
Major Story Arcs
Generation Lost - Tomorrow Is Today
During an assault on Max Lord's moon base, home of an out-of-control OMAC project that had overrun the world, Thomas was almost immediately infected with nanites and transformed into an enormous OMAC. Before Captain Atom was pulled back into the past, he destroyed the OMAC project at the behest of the surviving members of the Justice League, despite the fact that doing so would also destroy the base and likely kill all of them. The resulting explosion not only destroyed the base, but also a large portion of the moon. However, in a previous trip even further into the future, Captain Atom discovered a world with a moon that had been similarly destroyed where he met an incredibly elderly version of Power Girl. It is possible that Power Girl survived the moon explosion if it is indeed the same timeline.