The Brothers were all sent Halloween Masks they all thought came from Diavolo from the Mask Festival, but apparently. It was from a witch that the 2nd born, Mammon hadn't paid back a debt to. These masks were cursed for the wearer to act out their sins more, to have less control over their feelings, possessiveness and demonic urges. It was too late and Lucifer and his brothers already worn it.. And they desire nothing more than you and your soul.