Growing up, Sergio's life was anything but easy. He was born into Sellsnake poverty and was teased relentlessly for his appearance and shyness. He stayed mostly with his aunt Conchetta Albatroz after the death of his mother and his father's absence. He helped her in the marketplace, and even after joining the Sellsnakes, he continued to help and provide for her. 

Sergio created his alias, The Python, out of inspiration from The Viper and soon became dangerous. A black, masked figure armed with two constricting whips. He climbed Sellsnake ranks because of his skill and eventually met Ramses Castillo, who ended up grooming him into submission and loyalty. He became Ramses' bodyguard and killed anyone who dared defy his master.