Little is known about Enrico's past. Before coming to Bellezza, he was an ostler and reveals that he is still skilled with taking care of horses in City of Stars. Though described as handsome, Enrico is infamous for wearing a blue cloak and smelling unpleasant, particularly because he strongly dislikes taking baths.
During City of Masks, he has been spying on the Duchessa of Bellezza for Rinaldo di Chimici and learns that the Duchessa uses body-doubles when he pressures his fiancee, Giuliana, to reveal how she obtained a large amount of silver for their wedding. Enrico arranges for Guido Parola to assassinate the Duchessa; when Guido fails, Enrico performs the second assassination himself, rolling a bomb under the Duchessa's chair in the Glass Room. However, he unwittingly kills his fiancee Giuliana, unaware that the Duchessa had arranged for Giuliana to be her body double. When Rinaldo's plan to install his cousin Francesca as the new Duchessa fails, Enrico is assigned to kidnap and imprison Lucien Mulholland for Rinaldo's attempt to overturn Arianna Gasparini's election by accusing her of being a witch. After his business with the di Chimici is completed, Enrico is shocked to discover that Giuliana has mysteriously disappeared and he is devastated. He leaves Bellezza for Remora and continues to work for the di Chimici.
In Remora, Enrico is responsible for the abduction of Merla, the flying horse in the Twelfth of the Ram, and later that of the Ram's rider, Cesare Montalbano. He eludes capture again and reappears as the chief spy of Niccolo di Chimici in Giglia.
In Giglia, Enrico is known as the Eel and runs Niccolo's spy network and serves as Niccolo's right hand man in unsavory activities. Among his spies is Sandro, an orphan boy who gradually drifts away from Enrico as he spends more time with Brother Tino, Brother Sulien, and the other monks at Saint Mary-among-the-Vines. Enrico attempts to overcome his heartbreak from Giuliana's appearance and tries to become closer to Beatrice di Chimici, with no success. At the climax of City of Flowers, Enrico acts as one of Niccolo's seconds in Niccolo's duel against Luciano Crinamorte and is aware that Niccolo has poisoned one of the blades to order to kill Luciano. When he notices one of the duel's spectators is Silvia Bellini, the supposedly dead Duchessa of Bellezza, he realizes that the woman killed in the Glass Room must have been another double and she must have been Giuliana. Enraged that he had been responsible for Giuliana's death because of the di Chimici, Enrico switches the blades and gives Luciano the poisoned sword to use against Niccolo. With Niccolo's death, Enrico flees the city and severs his ties to the di Chimici.
During City of Secrets, Enrico reappears in Padavia and forces his services upon the Stravaganti and their allies, specifically Luciano Crinamorte and Cesare Montalbano. He continues to aid them in City of Ships, where he is awarded a medal for fighting in the Battle of Classe and attends the wedding of Beatrice di Chimici and Filippo Nucci.
During the events of City of Swords, Enrico follows Luciano to Fortezza, where a succession struggle has left the city divided and besieged. In the wake of the di Chimici army heading to Fortezza to free Lucia di Chimici from the rebels, Enrico gathers information from commoners that noblemen such as Luciano and Prince Gaetano do not learn due to their privileged positions. However, at the end of the siege, both Luciano and Enrico are arrested by the Grand Duke Fabrizio for the outstanding charges relating to the death of Grand Duke Niccolo. At the trial, Luciano's charges are dropped as a result of an obscure Fortezzan law and Enrico's charges are dismissed after Luciano successfully argues in court that Enrico is not responsible for the Grand Duke's death. The act leaves Enrico completely dedicated to Luciano, who comes to believe in Enrico's sincerity in wishing to serve him. During the Duchessa of Bellezza's wedding to Luciano, Enrico personally takes charge of the security for the event, including dealing with Vittorio Massi's sudden appearance at the wedding when Vittorio attacks the new Pope to avenge the death of his daughter.