The House of Namaru, also known by their modern sobriquet Devils, are the former heralds of God. Becoming the leaders of the rebellion against Him, the Devils began to use humans more than help them. When they fell, they were cast into the Abyss like the other rebelling angels. After the Abyss cracked and the Fallen could escape, the Devils turned to using their former allies in the same way they once manipulated people while still influencing mortals.
Lucifer is the most famous Devil, having lead the rebellion against God. His current whereabouts are unknown.
The Namaru were the last house to present themselves during The Fall. They were represented by Lucifer. A new kind of Namaru, the Qingu, appeared shortly there after to inspire humans to new heights of greatness.
Showing His wrath at their role in the Fall, God did not actually curse the Namaru. Instead, He ignored them completely, showing His complete contempt for them.