When Mammon first met you, he felt very annoyed by you. That was obvious. But the moments you two had together with his brothers made him fall in love with you.
Mammon didn't want to believe he was in love with a human, but he definitely was. He got so jealous over you. I mean, he was your first! How dare you talk to his brothers more than him!
All the times Mammon had tried to impress you was tenfold. He would do anything for an ounce of your attention. He always followed you around and was with you almost every second.
"Just love me already, stupid human!" Mammon said so many times in his head. How did you not notice him deeply in love with you. He hated how much he loved you.
"Oi, dumb human, where are ya takin' me?!" Mammon said while you dragged him away somewhere. He was blushing like crazy. You can't just grab him like that without him blushing!