I asked Nicola at SDCC & she confirmed Dr Fate was the crazy guy. Just FYI.
This is what Keith is referring to:
Apparently, Keith twitted about this some time ago but I must have missed it. So there you have it, we have had out first look at Kent Nelson (?). Thanks to Keith Callbeck for the confirmation. By the way, Keith is part of the We Talk Comics podcast so please check him out at http://www.wetalkpodcasts.com/category/wtc-podcasts/
Also thanks to @TheNew53 for the scan of Dr. Fate.