Zauriel is a Pax Dei (Biblical angel) who abandoned Heaven after he fell in love with a mortal woman.
He joined the Justice League and helped them defeat a rebel angel called Asmodel who intended to overthrow The Presence (DC Comics' version of God). He is armed with a sonic scream, an enchanted spear, and a flaming sword. He is an extremely useful ally during the League's missions due to his staggering knowledge on religion, history, and mythology.
Interestingly, the character was created by accident. When visionary writer, Grant Morrison, launched his series, JLA, he was excited on writing stories about Hawkman.
Unfortunately, the higher-ups at the company informed Morrison that Hawkman was off-limits due to his convoluted backstory. To get around this, Morrison devised another ancient winged religiously-themed superhero, Zauriel.
The strangest thing about having an angelic being on the team is how the other League members don't seem to make a big deal about it. Batman's an atheist. Doesn't Zauriel prove the existence of God? Shouldn't Christians be going crazy? Isn't it odd that a servant of The Lord is fighting alongside Plastic Man and the Flash?
And if you thought having an angel on the team was surreal...