I kind of thought they might make DC's return to the Silver Age complete, by making Hawkman an alien again. So the '100% alien' might refer to him, instead of the about 10% alien he is now (having Katar Hol's memories, probably a little of his DNA and using Thanagarian tech). Of course 'Kings Reborn' could also refer to Hawkman, who is a reborn prince, anyway.

Maybe that's just me. I see every clue there and think "That could mean Hawkman!"