Santos is the supreme leader and top commander of the Transformers Reaction Force or TRF in acronym, an international government-packed military organization whose main goal is to wipe out every single Transformer in Earth, regardless of faction, but later he helps the Autobots to save the Earth.
Santos is the leader of the TRF and a former Delta Force Operator who was born in São Paulo, Brazil and grew up in Phoenix, Arizona.
Santos led the TRF on a mission to Chicago when drones detected Transformers there. He encountered Cade Yeager, demanding where he's hiding the Autobots. However, Bumblebee arrived and went on a reassembling spree and killed many of his men. Cade then threatened to kill him until William Lennox arrived and encouraged him to stand down. Later, Hound arrived and threatened them with his Gatling gun, allowing Cade to ease the standoff. As Santos told Lennox on what side he's on since that the latter was a Autobot ally, he ordered a TRF sniper to fire a tracking device on Bumblebee. He later followed Megatron's Decepticon team into another mission to Cade Yeager's junkyard and pursued the Autobots when they beat it out of there. His TRF forces surrounded the abandoned city Cade was using as refuge. He controlled a fleet of drones which Cade had a heck of a time avoiding, but was forced into another retreat when the mother drone was destroyed by Cade. He and Lennox arrived in Fifth Fleet of the USA being in England a squad of Navy SEALS and TRF troops and pursued the HMS Alliance, which was being captained by Cade and Viviane Wembly. Arriving at the ancient Cybertronian ship, Santos's submarine was forced to use a narrow, perilous tube for entry after the gate closed behind Cade. He managed to make it in and engaged a knight who threatened Cade and Viviane. He then tried to convince Viviane to hand over the Staff of Merlin, only for her to turn the tables on them when she revealed she was the only one who could use it. Santos had to stand down. He rendezvoused with the rest of the TRF soldiers when the ship broke the ocean surface and they were provided with Ospreys to reach the ignition chamber after boarding the Knight Ship the Autobots were using as their main transport. He boarded the same Osprey as Lennox, Cade, and Viviane (and unknowingly Izabella and Sqweeks) and had a conversation with Cade. Having finally understood that his belief about all Cybertronians being enemies was the big tragic error, Santos and his soldiers removed the TRF badges from their uniforms threw them to the floorand and breaks the with TRF. Then the former TRF soldiers, Santos and Lennox reached the chamber and they targeted it with a nuclear strike after suffering many casualties during the final battle against the Decepticons and Quintessa. After the long battle, Optimus gave a speech before heading back to Cybertron using the Autobot Knight Ship.
Santos is the leader of the TRF and a former Delta Force Operator who was born in São Paulo, Brazil and grew up in Phoenix, Arizona. Like Harold Attinger, Santos was first ruthless about the Transformers, both Autobots and Decepticons as he believes them to be a threat on Earth. But in his eyes what he does is right, indeed, he ordered an airstrike to kill Canopy in order to protect Izabella and the other children present in the forbidden area of Chicago. He is also ruthless with humans as well as his own soldiers, indeed, after Bumblebee killed some of his men in order to save Cade Yeager and also when he tried to kill him using TRF drones after Dinobots destroyed the military convoy.
However, unlike Harold Attinger, he redeemed himself and changed his opinion when he allied with Cade and the Autobots in order to save the world from Quintessa and the Decepticons. He and the his soldiers tear the TRF badges out of their suit to make it clear that they no longer posed a threat against Cade and the Autobots.