"Hellbreak" 

Because Mammon was the demon lord, usually, only his subordinate who answered those calls and granted the wishes of those greedy beings. 

Mammon only came out in person in his chibi appearance to greet the 'customer' when the sacrifice offered was large enough and interesting enough. 

Usually, people like Jake were the ones who could directly summon him instead of summoning his subordinates. 

But why did this rich man suddenly become so poor?! 

The rich man with no money to spend was even worse than a genuinely poor person because Mammon could see all the wealth, yet couldn't touch it. 

So frustrating! Ahhhh! 

Mammon was so depressed that his consciousness directly disappeared on the spot, leaving Jake's body on the bed inside the castle. 

With this, Mammon also returned to Hell and he returned Atherton's other wing in a few seconds.