4 years ago - Zauriel falls to earth to win the heart of his charge, but she rejects him.
2 years ago - Zauriel learns of the coming invasion of Asmodel's Bull Host, but heaven will not listen to him so he turns to the Watchtower, which he subsequently joins.
1 years ago - Zauriel returns to heaven to demand assistance against the coming of Maggeddon. When they reveal their intention to remake creation, he chooses to stand with Earth, and rallies an army of angels, sacrificing his existence to save humanity.
When Hawkman was blacklisted from being used in regular comics because his backstory was completely inaccessible, Grant Morrison invented his own version of the character for his Justice League when he crafted Zauriel, a fallen angel.
There's a simplicity to the character that makes him fit into DC effortlessly, and we simply brought him in largely unchanged. Rather than struggle to find a place for him after his role in the Watchtower is fufillied,we've chosen instead to have him give up his life (or 'existence', as life is probably the wrong word) to save everyone during the battle with Maggeddon. If ANY character is seemingly built to be remembered as a martyr, it's the fallen angel.