Sun Xia was a little bit surprised by the question as it is common knowledge to the citizens of Western Moon Kingdom. Nevertheless, he answered, "Church of Doom is the most powerful organization of our kingdom. Even though it is called a church, it is more like a cult, worshipping the evil Taotie and wearing taotie masks too.
No one knows their origins but they came to the shores of Western Moon about three centuries ago. Back then, the Church of Light opposed their existence and termed them evil because of their practices but the Church of Doom was too strong with its leader said to be in the Supreme Realm.
They wiped out half of our army, hunted down the members of the Church of Light to the last man, and massacred more than 2 million citizens.