Mammon, the Lord of Avarice
"How about we make ourselvesss a deal?"
Mammon, the Lord of Avarice, is one of the greediest beings of all the planes. At one time his true form, which he can now only shapechange into, was a large, corpulent black pit fiend, with long, gold tipped horns and serpent eyes. After being cursed by Asmodeus, however, Mammon's true form is now that of a towering man covered in the scales of a snake, a long serpent's tail where his legs should be. Two long horns just out from his head, and his eyes are milky white, with no pupils or irises. He wears a large hooded robe the color of blood, emblazoned with a black diamond on the front and golden claws extending from the bottom, appearing as though they are reaching for the diamond.
Mammon is one of the most untrustworthy and hard to predict archdevils that rule the Nine Hells. The archdevil sees everyone that isn't him, even the gods, as expendable pawns in his plans to achieve all he could ever desire (which is pretty much everything), and as such is not afraid to stab others in the back if it means getting even a bit closer to achieving his goals. This, combined with the fact that Mammon always speaks in riddles, even while giving a direct order, makes it nigh impossible to tell if Mammon will let you survive another day or stab you in the back the moment you look away. It is this that makes him universally hated by other archdevils, particularly Dispater and Mephistopheles, former allies of Mammon that were betrayed by the Lord of Avarice.
Mammon's level of avarice is legendary amongst devils. The archdevil's desire for wealth nearly equals his lust for power, and many that deal with devils often prefer to make deals with him, despite the risk it imposes, for Mammon is quite possibly the only devil that will take gold, jewels and other expensive and valuable items in place of souls. However, even these deals can go horribly wrong for the poor fool that thinks it won't be nearly as bad, for though they don't lose their soul, they are quite likely to lose everything else, as Mammon takes all they ever had and adds it to his hoard.
The Cult of Mammon is composed of corrupt nobles, merchants and desperate beggars who are willing to do anything to get even a small piece of fortune. They are cruel and conniving with hearts consumed by greed, or at least will soon be. They hoard money, up taxes, and use exploitation and blackmail to ever increase their fortunes. Mammon himself also encourages them to make the less fortunate suffer, so that they may turn to him in their plight and join the ranks of his followers, soon to become what they once hated. Mammon's influence does not stop at them, however, for many monsters throughout the land have fallen under his sway. Most notable are dragons, whose natural greed makes them perfect candidates for his cult. His involvement with dragons has earned him the animosity of the goddess Tiamat, however, who wishes for his head on a silver platter.
Madness of Mammon
If a creature goes mad in Mammon's lair, within line of sight of arch devil, or due to Mammon's Touch of Greed, roll on the Madness of Mammon table to determine the nature of the madness, which is a character flaw that lasts until cured. See the Dungeon Master's Guide
for more on madness.
Spoiler: Variant: Alternate Spell
If one so chooses, they may replace one of Mammon's 3/Day spells with the following spell, which is cast at 5th level:
Mammonís Cash Shower
Casting Time: One action
Range: 300 ft.
Components: S, M (a handful of gold pieces)
Duration: Concentration, up to 10 minutes
Invoking the power of the archdevil Mammon, you create a large storm cloud in the shape of a cylinder that is 20 feet tall with a 10 foot radius, centered on a point you can see within range. The cloud begins to rain either copper pieces, silver pieces or gold pieces. Any creature that starts its turn in the radius or enters it must succeed on a Dexterity saving throw or take 3d10 bludgeoning damage and 1d10 of either acid (if raining copper), cold (if raining silver) or fire (if raining gold) damage. At the start of each of your turns, you can move the cloud up to 10 ft. in any direction within the spellís radius. The coins magically disappear after hitting the ground and are not usable.
At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the rain deals an extra 1d10 of damage corresponding to what is raining from the cloud.