Egidio Rossi is the eldest brother of Rodolfo Rossi. He was the first of his brothers to become a mandolier and a lover of the Duchessa. In accordance to the law that no mandoliers can be over the age of twenty-five, Egidio retired at the requisite age with a large pension.
With his pension, Egidio opened a workshop and stationery store that produced notebooks, paper, and pencils, many featuring designs that have been created by his brother Rodolfo. Lucien's talisman, an marbled notebook, originally came from Egidio's workshop. The shop is well known and Egidio's business has been properous.
Egidio lives across a bridge overlooking a canal from his brother Fiorentino. Though they are still regarded as handsome men at their age, they never married, most likely because they were the Duchessa's former lovers and remain devoted to her. As a request from the Duchessa, he and Fiorentino take in Guido Parola and teach him how to be a mandolier. In the epilogue of City of Masks, Egidio and Fiorentino praise their niece's sculling skills and later appear with Guido at the new Duchessa's ball for Carnivale.