Of course, it’s a Legion of Doom drawn from characters that already exist in the CW’s version of the DC universe, including Malcolm Merlyn, Damien Darhk (Neal McDonough), the Reverse-Flash, and Captain Cold.
We now know why John Barrowman (Merlyn) and Wentworth Miller (Captain Cold) were given deals that allowed their characters to appear in all the DC CW shows: it was for this. The Legion of Doom will be the big bad of season two of Legends of Tomorrow. having added Matt Letscher as the Reverse-Flash and Neal McDonough as Damien Darhk.
Why give this name to these characters? Executive producer Marc Guggenheim gave this answer, “For season two of Legends, we decided that the perfect antagonist for TV’s first-ever team of Super Heroes would be TV’s first-ever team of Super-Villains, recruited from the ranks of Arrow and The Flash’s deadliest adversaries. Being huge fans of the Challenge of the Superfriends, we’ve come to call this group our ‘Legion of Doom.’”
Luckily for the Legends, they’ll have at least a few members of the Justice Society to help them out. No casting was announced, but the panel did confirm that JSA members Stargirl, Obsidian, and Dr. Mid-Nite will be appearing in season two, joining Patrick J. Adams’ Hourman.