Mammon

Mammon has white, messy hair, tanned skin, and blue and yellow gradient eyes. He has on gold stud earrings and two silver rings on his ring and pinky finger on his right hand. Like all of the demon brothers, Mammon paints his nails and specifically wears white nail polish.

Mammon and Satan are the only brothers whose final design didn't change from their concept arts.

True to his title of 'Avatar of Greed', Mammon is naturally greedy and always seeking out opportunities to profit without putting much work. According to the chat First Thing in the Morning, the first thing Mammon does every morning is check his stocks. In Beelzebub's Devilgram Unspoken Affection, the results of the D.D.D. app "Demon Brain Scan" are that 90% of Mammon's brain is taken up by "money."

Although he's the second eldest, he acts immaturely when he doesn't get his way and is the biggest troublemaker of the brothers. He's egotistic and prideful, though it seems that it is only a façade to cover up his soft nature. He often refers to himself as "Ore-sama" and "Mammon-sama". "-sama" is a Japanese honorific given to people worthy of the utmost respect, so Ore (crude pronoun for me, I) -sama is, essentially, "The Great Me".

Mammon is also quick to lie, but not very good at it; in many stories and chats, he stutters when he denies something (even while texting). He has a tendency to shout whenever he's angry or upset (which is most of the time) as well as growl when he's irritated. He often praises himself when he thinks any of the brothers compliments him (even if they aren't) and thrives on being complimented, especially by MC.

He acts impulsively and often speaks before he thinks. It's because of this that Lucifer takes great precautions and enforces multiple rules that inevitably inconvenience the rest of the brothers and MC. Despite his rashness, Mammon is sensitive to changes and highly empathetic; he's the first to notice if something is amiss with his brothers or MC.

He's generally the punching bag for his brothers, and Beelzebub claims that all Mammon's six brothers look down on him in Belphegor's Devilgram, Hatred. He often complains about this, but rarely fights back physically. While being the second-born means he has a great deal of power, he's not much of a fighter. His typical response when getting into trouble — be that with his brothers, people he owes money to, etc. — is to run away. He's considered to be one of the fastest demons, such that not even Lucifer nor Diavolo can match his speed. He also doesn't lose control of his powers as easily as some of his brothers, which is likely why Lucifer entrusted him as MC's guardian during their stay in the Devildom.

Whenever there's a crisis, he's generally quick to come up with a plan that often leads to dangerous results, as seen when he used Leviathan's new game Dogi✩Maji✩Memorium to work out Lucifer and Satan's differences (unaware that the game was a dating sim). He also can be quite skilled at mentally challenging tasks if he puts his mind to it. One example of this how he struggles with math homework in his Devilgram The Mammon Way, but has no trouble once he's calculating money.

When it comes to romantic relationships, according to him in the Who's Your Type? chat, he sees them as an investment of time and money and greatly dislikes partners that asks for either of them from him. According to Asmodeus in the Popular with the Ladies Devilgram, Mammon attracts the "sassy and outgoing" types.