Antonio is a resident of Soleanna in Sonic the Hedgehog (2006). He is the ghost of one of the three musketeers of Soleanna (although the other two are unknown) and he is naturally very wise. According to legend, he was the hero responsible for saving Soleanna, and soon after, he and his companions had concealed treasure in a secret location. Only those who can prove their skill at flight, strength, and speed can acquire the treasure.
In Sonic's story, a historian from New City named Rossi explains the legend of Soleanna's three musketeers to Team Sonic, believing they are capable of obtaining the treasure. He tells them to visit Antonio at New City's clock tower. Antonio plays a large role in Sonic's eighth Town Mission, as he provides each of the three heroes a challenge of their abilities: Tails is given a flying speed test, Knuckles is given a strength test, and Sonic is given a running speed test. Impressed by their good performances, Antonio rewards them with the treasure of Soleanna.