Who's That Guy?

Okay, so. Who's the burly Monitor in the Anti-Monitor armor?

Where did he come from, what is he doing around, and why is he dressed like that? Is he the same Monitor we saw from the back in Brave New World? Does the world he's from in some way have an effect on the way he dresses?

And more importantly, does this totally destroy all the theories I've had about where the DCU is heading?