At first, Mr. Avericci appeared to be an affable businessman who was willing to help his clients find what they were looking for to shop and buy. However, in reality he is a selfish man who would do anything to satisfy his greed. It was also indicated that he was willing to renounce his humanity by selling his soul to the Devil to satisfy more of his greed and collect the souls of missing teens to pay off his debt, as his true form was that of a demonic creature.
Aside from wishing to repay the Devil so that he would not have his soul taken by him, it is also indicated that he had a fondness for mannequins, as he would transform his victims into them prior to giving their souls to his employer.
Starting off as a normal human being, Avericci grew up to become a greedy shopalohic. When he lost his money, he sold his soul to Devil for more, eventually becoming a demon himself. As part of the deal, Avericci was tasked to open and run a new business mall called Mall-halla in Riverdale in order to lure greedy teens so that he can turn them into mannequins in order to collect their souls and pay off his debt.
Avericci first appeared greeting Archie Andrews and his friends when they arrived to Mall-halla. Giving out special debt cards as they are short on money, he encouraged the kids to use their cards to buy his products. Due to the majority of many teens attending Mall-halla, many local businesses are being forced to close, including Pop Tate's restaurant, much to Jughead's dismay.
As days passed by, Avericci took the opportunity to turn the teens into mannequins after their cards have maxed out. He also casted a spell through the mall's speaker systems to make others forget in case they would notice and lure them back into the mall for more shopping.
After collecting the souls of Archie and his friends, Jughead was the last one to go. Avericci tried to convince him into using his card to buy some food at the mall's buffet, but remembering Tate losing his business, Jughead angrily refuses and rips up his card. Jughead's defiance then caused the spell to be broken, making him realize Avericci's true colors and plans. Jughead then vows that he will never let Avericci use his friends to pay off his debt.
Enraged by this, Avericci reveals his demon form in an attempt to kill Jughead, but the latter escapes and manages to free Archie and the other kids from captivity by ripping off their cards. As the kids finally escape from Mall-halla before its doors closed shut, Avericci pathetically begs for them to come back just as the mall finally crumbles down, squishing him to death.
With Mall-halla destroyed, all local businesses are booming back to normal (including Tate's), and it can be implied that Avericci is sent to Hell for his failure to settle his debt with the Devil.
His name is a pun for the term "avaricious", which means "greedy". This is more than fitting for his greedy personality.