Since Hydra's "Two More Shall Rise" card specifies picking two characters with leaderships, is the card able to be played if there is only one other leader on the board?
For example, if Red Skull, Master of Hydra is my active leader and is KOd, can I play the card if Strucker is my only other leader on the board, or is it mandatory that someone like Sin or Malekith is there as well to make it two?