The first year of the disease
Nick was not originally from London, and lived in the countryside before the spread of the disease, probably on a farm. At some point, he and his wife kept pigs, but it is unknown whether this was before or after moving to London. The couple eventually moved to London, and lived in a five-carriage train in Bank station. They also stockpiled canned food and other supplies which they found in train station shops.
Nick and his wife were able to negate the effects of the disease for a whole year, longer than any other known adults, by keeping children like farm animals. Instead of eating the whole child in one go, like most sickos, they kept the rationed their meat and only killed the next child once they had run out. This enabled them to always have child flesh in their diet, as each one could last them several weeks. The children chained to the handrails in the second carriage, and fed the unpleasant food which Nick and Rachel didn't want to eat. The children's muscles, especially their legs, would gradually atrophy from lack of use, and they would hardly be able to move.
About three weeks before he caught Small Sam, Nick found a girl named Rhiannon and brought her back to the train. at the time, they had four other captive children: twins named Jason and Claire, a boy called Mark Watkins and another girl who was too sick to talk. The sick girl was killed off soon after, although Nick and Rachel didn't eat her for fear of catching her illness.
Mark Watkins had been with the couple for a long time, and could hardly stand up due to muscule atrophy. He was killed and butchered soon after Rhiannon arrived. Rachel and Nick claimed that they had taken him up to the surface because he was no longer sick.
Capturing Small Sam
Nick was at King's Cross when he encountered Small Sam, who was running from sickos. He used his sawn-off shotgun to kill the sickos and then carried Sam down the tracks to Bank station. Once inside the train, Rachel fed Sam some stew with a sleeping drug in it, and he fell asleep. Once Sam was asleep, Nick handcuffs him and takes him through to the children's carriage, where he attaches the cuff to a chain hanging from the handrail.
Two days after Sam was captured, he and Rhiannon got rescued by The Kid. As the trio were escaping over the platform, Nick's cat, Orion, saw them and shrieked. Nick then looked out of the train to see the kids, and quickly grabbed his shotgun before coming out with Rachel to chase after them.
He and Rachel split up at the bottom of the escalators, where the three children are hiding behind some rubbish. Nick went back into the tunnels to look for them, while Rachel checked the ticket hall. He then quickly came running back, after Rachel heard Rhiannon wheezing behind the cardboard and called to him. He saw the kids as they were running up the escalator, and shot at them, hitting Rhiannon. Leaving her with Rachel, Nick chased Sam and The Kid up the escalator and out into the daylight.
Nick soon managed to grab Sam, who was disoriented by the bright sunlight after being in the darkness for two days. As Nick was about to shoot Sam, The Kid leapt at his arm. This caused the shotgun to smash into the base of a statue while it was firing, bending it out of shape. The Kid fell heavily, and was unable to get up. Nick then drew a knife from inside his coat, and swiped at Sam twice, who then dashed under a van. Nick grabbed his ankle and dragged him out, holding the knife over Sam.
It was then that Nick noticed what the sunlight was doing to his body. His life in the darkness had left him with no resistance to the effects of UV light on diseased adults. The disease accelerated rapidly within him, causing boils to break out all over his skin. Within seconds, his eyes had burst and his face had swollen to a huge size. Nick's skin then finally split, with his body disintegrating and insides spilling out onto the pavement.
Nick was grumpy at the best of times, and outright murderous at worst, calling himself "Satan his-self". He saw children like cattle, as animals for him to keep and slaughter when the time came. In his final minutes, he was shown to be incredibly sadistic and vengeful, as he wanted to watch Sam die painfully and slowly.
He wanted to see the fear and pain in his eyes before he finished it. He wanted the brat to know full well what was about to happen to him. Let him see the knife. Let him anticipate what it would feel like when he brought it slashing down.Nick's thoughts as he prepared to kill Small Sam
However, it is worth noting that the disease causes adults to want to eat children (to slow it down) and that in his final moments, the disease in him was accelerating rapidly. It is possible that these final thoughts were more the disease in him taking a stronger hold rather than his true personality.
He had a shaven face and long, untidy dreadlocks, although he wasn't black. He wore jeans and a knitted sweater, with a heavy overcoat over the top. He was a smoker, and still had a supply of tobacco a year after the disaster. He carried a large battery-powered torch, a sawn-off shotgun and a large knife. His accent was "a soft country accent, sort of fruity".