Sean Ramsey was the leader of the Immunes who acted as the main villain for most of the second season.
During the Red Flu pandemic Sean served as a lieutenant aboard the Achilles alongside his brother Ned. Unknown to the rest of the crew a lieutenant was infected with the virus and spread it to the rest of the crew. Everyone aside from Sean and Ned died of the virus and Sean stayed calm reassuring his brother that they will get home. At unknown points Sean was promoted to lieutenant commander.
Sean came to strongly believe that he and all Immunes were specially chosen to carry the torch for humanity and would stop at nothing to see this vision come true. As a result, Sean started recruiting fellow Immunes and formed a cult with his ideology and trained a crew to run the Achilles. He eventually created a vast network for the Immunes and recruited fighters from Europe to his cause and started a war for control and the extermination of Non-Immunes. After they conquered Europe Sean started sending his followers to the US in preparation to take control there too.
Events of The Last ShipEdit
When Sean learns that a US Navy ship has arrived with a cure to the Red Flu Sean moves up his invasion of America a month ahead of schedule. He sends Ned to lead a team of Immunes to raid a hospital ship called the Solace to destroy the lab, kill everyone there and get the locations of the other labs. In the process the US Navy ship arrives and kills eleven Immune sailors, seven of whom report directly to Ned, rescues half of the remaining Solace crew and captures the Immune with the flashdrive of lab locations: Juan Carlos. Ned and the rest of his team manage to escape unscathed or just wounded. (“Solace”)
Sean has the man who tipped them to the Americans having a cure, Dr. Niels Sørenson, brought onboard the Achilles. Sean tells Niels how he got the Achilles, how it formed his ideology and recruited fellow Immunes to help run it. When Ned pulls a gun on Niels, Sean tells him to lower his gun so Niels can sort through the paperwork they got from the Solace. Ned lowers the gun while telling Sean he doesn't trust Niels and Sean responds that he doesn't care and Niels will remain their guest. Sean listens to Niels as he tells them about the Nathan James, Dr. Rachel Scott and its captain Tom Chandler. When Sean hears that Chandler defeated renowned Russian Admiral Konstantin Ruskov twice and killed him, Sean rejoices at the news he has been neutralized. Niels stresses caution when dealing with Chandler but Ned states a destroyer can't touch a sub and Sean agrees.
When Declan detects a ship going south very slowly, Sean determines it has to be the Nathan James going slow to avoid detection and Sean orders them to plot a course to intercept and to arm their torpedoes to fire. When the ship starts to move away Ned urges Sean to engage them before Sean says to mind himself. Max and Ned urge Sean to act but Sean tells Ned they need to get closer to pick up Juan Carlos. Ned questions how Juan is supposed to get off the ship, if he's even still alive. Sean says he'll find a way but then Ned questions Juan's loyalty and Sean says it isn't a matter of loyalty but belief. After the ship disappears from radar, Ned suggests firing at random but Sean rebukes this as relying on dumb luck and when Ned brings up his seven Immunes comrades killed on the Solace, Sean angrily replies that they were his men. Sean then calculates a course to intercept the Nathan James on the other side of the Bahama Bank and urges Ned to be patient.
Sean visits Niels while he tries to sort through the various documents to ask about his progress. Niels replies that the Solace was the right place but they didn't get what they need from it and they are seriously preparing to distribute the cure and Sean mentions that they will handle that. Sean elaborates that they will sink the Nathan James and when they send Dr. Scott on the first life boat they will capture and kill her. Niels says that plan seems a little risky and Sean reassures him that Juan will find a way off that ship and join back up with them.
While the crew start to argue with each other over their next move, Sean tells them to stop and give him their options. Declan tells him he can't see the ship on passive sonar and Max say their torpedoes are armed, loaded and ready to fire and Sean wonders why they can't hear them. When Ned suggests going active sonar Sean says the Nathan James will hear them but Ned says they don't have much of a choice now. After Max says he can target the ship in less than a minute, Sean gives the order to go active sonar and target the Nathan James. Both fire torpedoes at each other and Sean orders a crash dive to avoid them. Ned wonders what they are hitting, Sean answers that the Achilles is scrapping the canyon walls and Sean gives his men a speech to show resolve and courage at how they are "the selected."
A few moments later, Niels barges onto the bridge with the location of one of the labs housing Dr. Scott's mentor, Julius Hunter and says he will have the locations of the other labs. Sean sends Kevin MacDowell's men to raid the lab and kill everyone for the locations and transmits them to Sean. Sean then has the Achilles surface and launch tomahawk missiles to destroy the labs in the US while ground forces take out the other two in Istanbul and Lisbon. After the labs are destroyed Sean tells Ned that now they will take over America instead of taking out the Nathan James. (“Achilles”)
Sean takes a team of Immunes to shore in Florida, including Ned and Niels and congregate near a safe zone outside a mall in the Everglades. Sean tells Ned that MacDowell theorizes that there are ten thousand there and five percent maybe Immunes. Fifteen million Americans waiting to join them until Ned doubts if they will all follow Sean's "we are the chosen" act. Sean firmly states twice that it isn't an act and Ned mentions the only cure left in the world is on the Nathan James and suggests hunting it instead of what they are doing now. Sean reminds Ned that the Achilles is useless until they repair the damage caused from scrapping the canyon walls and once it is done Ian will resume hunting the destroyer. Ned starts telling Sean that they should just destroy the ship and go home. Sean tries to explain that he has a plan but Ned say it is a bad plan. When Ned questions why Niels is still with them, Sean reminds him that Niels is the reason they found the labs and that they are going to use him to infect as many survivors as possible and find more Immunes.
Sean and Ned wait for Niels to return in an abandoned house when he arrives on a bike, reporting he infected everyone in the safe zone. Ned finally loses his patience with Sean and calls him a coward, using this American invasion as a way to avoid his responsibilities at home and that destroyer and Sean pulls a knife on Ned. Sean then dares him to call him a coward again and offers him a choice: help him in creating his world of Immunes or join their mother in the grave. Ned jokes about Beyonce possibly being immune and both brothers laugh it off and hug.
After a large number of Immunes gather in a hotel, Sean delivers a speech and professes his love for his fellow Immunes and their growing numbers across the country. Sean plans to head to New Orleans and spread their message to those who have not heard it yet and says America needs an American leader. He then reveals that Jeffrey Michener is twelfth in line for the President of the United States and with the others dead, he is the President and will lead America, making it great again. Ned, confused, asks why Sean never mentioned him and Sean just reassure his brother that he has a plan. (“Long Day's Journey”)
Sean and his team guard Michener while he shakes hands with the Immune citizens gathered in the hotel. Sean later thanks MacDowell outside the hotel for their turnout today before he leaves with his followers. Ned comes up to Sean, telling him he still can't get in touch with the Achilles and Sean says it could be a problem with the equipment they are using to broadcast to each other. When Ned suggests the Achilles could've been sunk, Sean brushes this off saying there is nothing they can do if it is, despite Ned's protests. Sean then orders Ned to accompany Niels as he tests a new way to spread the virus on a group of people living in a nearby trailer park.
After a bomb scare causes a riot among the Immunes, Michener is taken back to Sean's suite under armed escort with a new guest. Michener introduces Sean to him as the man who saved his life from a man who assaulted him in the chaos. Sean personally introduces himself to the mystery savior and thanks him for his actions before trying to send him away. The man suddenly states that there are more then two men guarding the American President and Sean agrees. Sean tries to assign Giovanni to POTUS detail before Michener insists an American, namely the man who saved his life, should be on the team. The savior gives his name as Tommy and Sean interrogates him on Tommy's profession, his family and how he came here. When Tommy mentions he came on one of the buses, Sean reasons he must have met MacDowell along the way. Tommy mentions he was a good speaker and Sean has James hand him a gun. Sean cocks it and subtly points it at Tommy while questioning him some more. After Tommy tells Sean he believes he was chosen to be here, Sean hands Tommy the gun and welcomes him to the fold.
After a convoy lead by Ned was attacked by people from the Nathan James who infiltrated their operation, Sean orders the President evacuated to the Achilles, all exits sealed and no one leaves the compound to ensure others inside can't escape. Ian radios in from the sub and Sean asks where he has been and Ian reveals the Nathan James blew up their repeater, preventing them from communicating any further. After Sean sees a van rushing off with Tommy, really Comm. Chandler, driving, he orders his men to stop them and tells Ian to blow up the destroyer. After they escape with both Michener and Niels in custody and Ian fails to sink the ship, Sean throws things on the ground in frustration and he wonders how this could've happened. Ned turns to Sean mentioning how he lost them and asks what he is going to do now. (“Alone and Unafraid”)
When Michener is first brought onboard the Nathan James, he inserts a flashdrive of Sean's video messages to other Immunes and Michener personally onto a computer provided to him and watches them while the crew monitors him. (“Safe Zone”)
After Sean had a fleet of civilian ships blown up and forced the Nathan James to deploy counter measures to avoid being hit by the Achilles' torpedoes, Sean hails the Nathan James on the radio. Sean gloats on how his men worked hard on those explosives and Chandler challenges him to a straight ship to sub battle with no civilians to hide behind. Sean then reveals he manipulated events this way to multiple the number of enemies the Nathan James has. Sean then releases a doctored video through Valerie Raymond's network making it look like the Nathan James open fire first and destroyed the fleet themselves. (“Friendly Fire”)
Sean sends a video message to the people in the area giving a fictionalized account of events to further damage their credibility. Sean claims he came as a friend and ally to the US Navy before he learned they had weaponized and released the virus and covered it up afterwards. Sean then rallies the people against the Nathan James for destroying the civilian fleet and being part of a conspiracy to take over America and killing everyone who gets in their way and uploads redacted files supposedly supporting Sean's claims. Sean ends his message declares to Tom Chandler that they are coming for him while presenting himself as a hero.
While working on a manifesto in his room, Ned comes in to tell him that the Valkyrie System has been destroyed by some regular American citizens after they spotted the Nathan James there. Sean is pleased that the people have believed his message and shows Ned his manifesto and urges his to get a copy to MacDowell and all their followers in Florida. Sean mentions Ned is in there and compares them to Moses and Aaron saying their mother would be so proud of them. (“Valkyrie”)
Sean orders his Immunes to use the civilians to block all channels leading out of the Mississippi River, where the Nathan James is hiding save for one to force them into a confrontation. On the Achilles, Sean call this a great day to sink a ship while waiting for news on the destroyer's location alongside Ned. When they get news that the Nathan James has been sighted in Quarantine Bay, outside their blockade, Sean assumes they must have slipped past the blockade before it formed. Ned criticizes the America armada before Sean reminds him that Ian is on land with a rocket battery for this reason and orders Ian to get into position to fire. Sean orders the Achilles to set course for Quarantine Bay. When the ship appears to be moving faster than it should be, Sean realizes Val is still alive and spoofing messages to make it appear they were in Quarantine Bay and moving north-northwest.
When Declan swears he heard something and asks about going active sonar, Sean tells him to hold off. Sean waits, anticipating a confrontation soon and orders Oliver to stop the sub all together. Declan sees the destroyer on radar and Sean realizes they are right above him. Sean orders them to go full speed ahead while staying under them until they reach deep water so they can dive and fire their torpedoes. As soon as they dive Sean give Declan to green light and Declan orders all torpedoes fired immediately while Sean orders an emergency dive to avoid torpedoes fired on them by the Nathan James.
One torpedo hits the Achilles and Declan says they need to surface so the hull won't crack and Sean yells at him to shut up. Sean orders Oliver to surface while facing the destroyer and lead them to the rocket battery. Sean has them prepare torpedoes to fire but as he prepares to fire their own rocket battery fires on them instead, having been commandeered by US Navy land forces. His crew attempt to abandon ship when Sean and Ned pull guns on them while Sean orders them back to their posts saying they are "chosen". Sean is last seen laying on the floor of the Achilles as it has sunk to the bottom of the ocean, screaming in anguish next to Ned's dead body over his ruined plans. (“Cry Havoc”)
Sean and his Immune Army were arguable most devastating villains the Nathan James have ever faced. His actions left thousands dead in his campaign to have the Immunes inherit the Earth which became more commonly known as the Immune Wars. His campaign is notable for beginning in Europe where his cult completely took over the region and killed most of the other people living there who weren't immune. He sent his followers to America where he directed them to pass out infected blankets and sleeping bags, intentionally infecting and killing people who weren't immune.
After he heard about a cure that had been developed, he came to America to destroy it along with anyone working on it starting with the Solace which lead to the death of fourteen members of the crew, including the ship's master and Chief Mate Gonzalez. He gave the order to raid Dr. Julius Hunter's lab, who was executed along with his staff, for the locations of the labs across the world. As a result, Sean had all seven labs destroyed either through raids or launching missiles from the Achilles. This resulted in hundreds killed in Lisbon, Istanbul, Phoenix, Salt Lake City, Madison, Topeka, and Baltimore. Sean directs Niels to infect a mall turned into a safe zone to find more Immunes, killing roughly nine thousand six hundred and eighty people.
Sean then began a smear campaign against the Nathan James to try and prevent people from being cured. He destroyed an entire fleet of civilian ships killing ten thousand people on board and framed the Nathan James for it. As a result a group of civilians attack an oil rig where the Nathan James sent some of its men killing BM Walker, SCSG Lynn, Lt (jg). Andy Chung and Israeli Lt. Ravit Bivas. As a result of Sean's actions the cure took longer to distribute and resulted in the deaths of many citizens infected with the virus. They also left many survivors, most notably in Europe and the Nathan James, emotionally scarred.
Even in death Sean's actions had a lasting effect after his defeat and the truth about his actions were revealed. Most of the Immunes surrendered in exchange for pardons from President Jeffrey Michener save for Kevin MacDowell who led one final attack to try and turn America against the Nathan James by exposing a group of citizens looking for the cure to infected citizens. The plan ultimately failed and everyone, including the infected, were cured but as one last act of revenge, one of MacDowell's followers, Curtis, shot and killed Dr. Rachel Scott in revenge for destroying Sean's dream of a world inhabited by only Immunes.
Europe and the surrounding areas still struggled to survive years later. During the Red Rust crisis, the British betrayed the Americans to get plague resistant crops because of how desperate they were to feed their people. Part of this was because they struggled to keep what people they had alive after most of them were massacred in the Immune Wars and the Americans took so long to distribute the cure to them after the Immunes raided and destroyed the labs in Istanbul and Lisbon.