The Dark Soul Mask Master

Legend has it that when the Creator God made the world, he asked a divine craftsman to forge four masks to speed up creation. These masks were given to his four chief subordinates to aid him. They were the Blood Soul Mask, the Artifact Soul Mask, the Radiance Soul Mask, and the Dark Soul Mask. Each mask had a different appearance and provided different enhancements. Because the four subordinates often wore masks, later generations called them the Demon Soul Mask Masters. The masks could change their appearance, and the masters could use both the masks and the power of the demon souls residing within them. It is said that there are four such masks, and obtaining even one grants immense power. — Description from novelcodex.org