Greg Thorne, later known as St. George, is the main antagonist of The Enemy series and makes an appearance in all seven books. He is shown to be extremely intelligent and is blessed with the ability to lead armies of grown-ups throughout the whole book via the use of telepathy that all the grown-ups posses (this may be attributed to the fact that he was the last grown-up on Earth to be infected).
St. George is described to be a fat, but well-muscled, boil covered, bald man who wears a pair of wire-framed glasses with no lenses perched on his squashed rotting nose. Random tufts of hair sprouted from his otherwise bald scalp on his immense, great cannon-ball of a head that lolled around over his chest and that his head was to big for his neck. His nickname comes from the fact that he wears a grubby white vest with the red cross of St. George on it. The name was first introduced whilst Shadowman was tracking the huge group of adults making their way towards the centre of London.
St. George makes his first appearance in The Enemy, where standing still in the middle of the pitch in the Arsenal football stadium, staring at Small Sam, who was situated in the hospitality box, looking across rows and rows of red seats towards the pitch.
He is then shown leading an army of grown-ups towards the Holloway crew, who had managed to position themselves into battle formation. Despite having strength in numbers, he was unable to defeat the Waitrose and Morrisons fighters and was forced to retreat with his army.
Some time later, Callum spots St. George trying to break into the Waitrose supermarket, along with Man U, Bluetooth, One-Armed Bandit and Spike. After a few days of persistent effort, St. George and his crew manage to break into the supermarket.
The last chapter in the book shows St. George standing in front of his army, with Callum's head on a pole. He then proceeds to march along with his army and goes around destroying every car on the road.
Being set just over a year before the events of The Enemy, the second book shows who St. George really was before becoming infected.
St. George is first introduced as Greg Thorne, a renowned butcher who ran an organic butcher's shop in Islington, with the slogan Meat Is Life. He had been on a few television shows, such as The One Show and had won many awards for his sausages, being Butcher of the Year for two years in a row. He drove a bus with a big group of kids on board including his son and the other main characters. He fights the disease by keeping meat from a child he killed at a barn where he lived with his son at the first outbreak of the disease. He kills his son, Liam Thorne, by strangling him in his sleep when the symptoms of the disease set in and he becomes more aggressive. He attacks the kids on the bus when they confront him about his son's death. His bus is destroyed. With the deliria of the disease he only remembers that Jack and the other main characters were the cause of his son's death. He spends the rest of the book stalking the boys and kills Bam when they separate from the other kids. He also carries the dead body of Liam wherever he goes, until dumping it off a bridge.
After the events of the Dead, Greg continues to build his army in the stadium until a fire starts forcing them to retreat. Shadowman is currently in the stadium at the time, and quickly escapes, fleeing to a nearby apartment building where he hides watching Greg's army grow. Suddenly, he is ambushed by the One Armed Bandit and a group of sickos, which he kills after blacking out many times due to a concussion caused earlier by Jester. He then swears that he will monitor Greg's army and kill every single one of his right hand men.
Shadowman meets a group of kids who believe that Greg and his army are all false. However, one of them is eaten and the others attempt to escape. Bluetooth attacks one of the group and she is knocked unconscious. The leader of the IKEA kids, Saif, then attacks the Fear (Greg's army) but they are ambushed and very few of them escape. Shadowman sees the chaos and decides to head off when he is ambushed by Bluetooth and his small mini gang. Ed's group later find him and kill them all, including Bluetooth.
Greg's army begins to grow hugely, and he marches off through England to gather an immense army for war.
As Greg's army grows immensely, he marches through the countryside where Ella and Malik encounter a small flank of the army, which pushes them out of their farm base and through the countryside. Meanwhile, back in London, the kids are noticing that the sickos are disappearing. The book wraps up with Ed's grouup finding out that Ella was just where they were, before Mr. Three screams that everyone is in danger and they need to return back to London.
By this time, Greg's army, The Fear, has become almost unstoppable. It heads into London, where every kid left has to gather into a huge group to fight them off. A massive battle ensues, before which a kid is killed by Man U after being impaled by an iron spike. During the battle, David is siding with Paul and he is using Paul to save himself from the sickos. Jester sacrifices himself to end David and Paul once and for all. Meanwhile, the battle is becoming easier to win, but everyone is becoming overwhelmed by the army. Then, Shadowman along with Ben and Bernie drives into the sickos with hot wired cars that have gasoline cans strapped to them, bowing up huge portions of the army. Ed then has a final battle with St. George, decapitating him and killing him, but Greg's headless body still tries to slice at Ed one last time before finally failing.