Amon is a black haired bat, with golden eyes and a gold earring. He is usually has a sly look on his face as if he was planning something.
Mamon is the opposite of Amon. He is a white bat with blue eyes. He doesn't have an earring, and he is usually seen with a cute smile.
Neither is seen without the other.
Ranked 7 among Solomon’s 72 pillars and a Marquis of Hell that leads 40 armies. Originally worshipped as the supreme god in Egypt. Later, he was associate with other cultures, and changed into "Wind deity” and “Fertility god”.
Characteristics Has the head of a owl or nightjar, the body and fang of a wolf. The tail is that of a snake. His ability is to grant knowledge of everything about future and past, and knows very well about humans relations, especially love.
One of the seven deadly sins. A Fallen Angel of greed that fits avarice. He too was similarly originally a god of riches(angel), but became enthralled with gold and became a demon.
Characteristics He commands of the mining team that excavates vein in the active volcanos in Hell. The vein of gold dug up by him was provided to Hell’s palace - Pandemonium. The one who taught humans about originally hidden veins was Mamon." 
According to the fanbook, Amon and Mamon are both Nephilim.
Amon and Mamon • Baphomet • Eligos • Gilles de Rais • Gilgamesh • John Dee • Lamia • Leonard
Belphegor • Empusa • Lamashtu • Leviathan • Lucifel Rofocale • Pluto • Astaroth the Second • Behemoth
Adrian Swallow • Barton Twining • Bianca Clifford • Elliot Eden • Mary • William Wynn Westcott
Arthur Christian • Cassandra • Ernest Crosby • Tamar • Elizabeth Dale