Just finished watching the TC for Earth 3 and there's a Deathstorm emblem in it. He's not in the game. Possiblea future boss fight.
I’m sure they’re going to follow up on this episode’s story, and when they do we’ll get Power Ring, Atomica, Deathstorm and Grid. ^^
Power Ring was Mentioned by Owlman in one of the Raids. And his Emblem was in the Earth 3 time capsule, so I'm not sure about him or Deathstorm at all for that matter. I'm hoping this isn't just a 1 part DLC; hope it becomes a trilogy.