Aldo Desantis was a high-ranking doctor of Prophet 5. He may have also been a subject of Project Helix.
Before Season 5[]
Desantis used to work for Renee Rienne's father until one day they became enemies and he decided to invade his house. While her father hid Renee in the closet, Desantis and a few of his men abucted her father and injected him with an anesthetic, presumably killing him (Out Of The Box).
Season 5[]
Desantis had been cryogenically frozen for 23 years and was revived by Nuridium and Rienne. After waking up, Desantis pretended to be her father and she, Sydney and Thomas Grace had to protect him from French mercenaries. However, unbeknown to everyone, Desantis contacted them with a beacon, indicating they actually worked for Prophet 5 and they were rescuing him, not abducting him. Desantis was successfully rescued by the agents and was sent to a hospital in North Korea, telling Gordon Dean who Rienne was (Out Of The Box).
Upon hearing of The Horizon, Desantis sent Kelly Peyton to San Francisco to steal files about Vaughn and later had Dr. Burris kidnap Sydney while he watched. Unfortunately, Rienne spotted Desantis and shot his van to pieces, killing all of his men and hitting Desantis in the chest (The Horizon).
Wounded, Rienne and Jack interrogated Desantis in order to find Sydney. Jack took out a knife and cut off his right ear, telling him that he'll never survive the blood loss. Desantis told him it doesn't matter where Sydney was, but where she was going. During the interrogation, Rienne found his notebook about an address in Hungary. Jack put a gun to his head and demanded to know of the address, but Desantis said Sydney wasn't there and that he was prepared to die. With no other option, Jack handed Renee the gun and walked away, leaving her to shoot Desantis twice (The Horizon).