Pietro is a resident of Soleanna in Sonic the Hedgehog (2006). He is the captain of the Soleanna Royal Guards. He can be found standing next to the fountain in Castle Town, where his duty is to guard the gate leading to New City in order to keep out suspicious individuals.
In Sonic's story, Pietro gives Sonic his fifth Town Mission. At first, Pietro claims to be a lieutenant and that he is not in charge of the gate to New City, so he cannot let Sonic through. However, he gives Sonic the challenge of guessing who the real captain is. After talking to the other guards, Pietro admits that he had tricked Sonic all along - he is the real captain. He was trying to keep Sonic away from New City as he did not want anyone else involved in Soleanna's business, but he realizes Sonic's capability of saving Princess Elise, after which he grants him access to the city.