The hospital theory is that all the kids of KND are patients in hospital and the nurse told them they were a secret squad of agents to cheer them up.
Numbah 5 was suffering from bad injuries given to her by her mother.
Numbah 5's parents had divorced and her dad left them penniless.
Her mother blamed all the tragedy on numbah 5 and beat her.
This led Numbah 5 to be the mother figure of their group as she wants to be a better mother than her's.
Numbah 4 had come from a rough neighbour hood so always had to be tough and aware of his surroundings.
He was sent to hospital with serious injuries after being mugged by a man with a knife.
Due to Numbah 4's tough nature he didn't back down and so was stabbed.
Numbah 3 was born to a family of drug addicts.
Her parents would often abuse her and she decided to take her mother's anti-depression pills.
Once she had taken them, she believed everything was good.
One day, her Dad shot her mom.
When she walked in on the murder, she couldn't realize anything bad happened since the pills heavily affected her mental state.
Her dad noticed her standing there and shot her to leave no witnesses.
She survived, but needed a liver transplant.
Numbah 2 was born to a loving mother and father who allowed his creativity to flourish.
He was praised and cherished, but his uncle, who had the same abilities was never encouraged as a child, was jealous.
Numbah 2's uncle overfed him.
Even when Numbah 2 refused, he was forcefully stuffed.
The boy eventually had to go to hospital as he was so obese that he would get seriously ill and had a high chance of heart failure.
Numbah 1 had a dad with Alzheimer Disease, so he always had to look after him though he didn't mind.
His dad was a nice guy and before losing his mind, was always kind to Numbah 1.
His dad was the only adult Numbah 1 liked since his mother left him and he felt the doctors and nurses didn't care about his father and weren't trying hard enough to save his father.
One day when he took his dad to the hospital, Numbah 1 puked randomly.
He was admitted and it was discovered he had cancer.
This led him to hate adults more as he felt he was being tortured with the needles and various medications.
In the children's ward, he acted like a leader to help the other kids feel better just as he had with his father.
The KND was then formed to war against the adults as they felt imprisoned in the ward.
The other members were of past kids who had come and gone while the teenagers were seen as enemies as they had their own ward which went against theirs.