What is The Ninth Gate?

The story follows a unique fallen angel known as Gale Solstrum, one who can bind the power of light and darkness to his will. After he defends a group of ostracized angels and demons from their would-be executioners, they form an alliance known as The Nine Gates. After coming to realize that neither God nor Lucifer would try to spare humankind from their wars, The Nine Gates find meaning in their existence to protect man from threats that they could not face alone. Ranging from rogue demons to ancient deities, The Nine Gates are tested in their bonds and strength again and again.