David King is the delusional and power hungry leader of the kids at Buckingham Palace. He rules with an iron fist punishing people for insubordination and not allowing anyone to leave. He keeps the remaining members of the royal family and plans to be king of England. He is a strong leader who rules with an iron fist - holding hundreds of kids in his palace to strengthen his ranks.
In The Enemy
David first appeared welcoming Jester's return and the Holloway crew's arrival. David introduced Franny to the crew, and he is seen talking to a bunch of kids about the organised condition in the palace. David later treated them with nice food in the evening.
During the meal, Blue talked with David, and Blue called him "Dave", intentionally or otherwise. Blue told him "You ain't going to be organizing me", voicing his displeasure about David lording up in the palace. Later, David showed them the "Throne Room", which consists of nothing but shambling grown-ups, and David explained his plan to the crew, to put what's left of the Royal Family on the throne, to unite all of London. Whitney objected to this plan, and called David "crazy". At this point, David rages on Whitney and shouted at her, until Whitney grabbed him by the collar and warning him not to shout at her again. David later hinted that there are problems with the camp at St. James Park, and wanted the crew's help to "sort them out".
Later, David was negotiating with Carl, the second-in-command of Just John, to make peace with the camp. John insists that the deal would be made if Achilleus won in a fight to the death with him. After speaking with Achilleus, David agreed, ignoring Maxie's protests.
In the fight, David acts as the referee, but the fighters completely ignored him and charged at each other. After the brief but bloody fight, Maxie was seen arguing with David, thinking he has gone too far this time. Maxie threatened to take her crew away from the palace, and this might have shook David to an extent. He sent her to see Blue in the infirmary.
As Maxie and Blue, having the same opinion, talk about leaving the palace, Rose signaled David by using a candle. David locked them up in the infirmary along with another girl (which is later revealed to be Brooke) to make the crew stay.
Later, Maxie and Blue led the Holloway crew, along with Andy (Big Nose), a guard in the palace that had defected from David. David tries to stop them from leaving by force, but failed because of the help of Ollie.
In The Dead
After Jack and Bam's death, David and his crew (much smaller than in The Enemy) found Ed surrounded by sickos. David helped Ed to get out of the mess, and seemed to be quite fond of his gun. David requests Ed to bring him to see Jordan Hordern.
Later, when Ed and David's crew arrived at the Imperial War Museum, DogNut reminded Ed of Jordan's rules and tries to stop them from entering, but failed. David was later seen negotiating with Jordan for weapons. In the talk, Jordan told David "You remind me a lot of me". David later heard his crew fighting with Jordan's, and helped Jordan sort the mess.
Later, David was seen helping the lorry to clear the road. He shot a kid and told the other kids to move the cars out of the way. They seemingly got across the bridge successfully.
In The Sacrifice
David makes no major appearances in The Sacrifice. He was mentioned by Nicola. He was mentioned by Dylan Peake (Shadow-man) as a bastard that resembles every dictator that had come before him. He makes an actual appearance while talking to Pod.
In The Fallen
David makes a minor appearance in the fallen trying to understand why the royals had become "sentinels" when Paul appeared claiming to have the ability to control them.
Personality
David was seen as a hypocritical, pragmatic, self-centered, hegemonic and power-crazed dictator, and he expects everyone to do as he told them. He suffered from an extreme superiority complex, in that he despised anyone who didn't do as he told them. These factors make it safe to assume that he has an overdeveloped sense of self-righteousness, believing that he should have something simply because he wants it. It is also implied that he suffers from an extreme God complex, as he initially believes that he is better than everybody else in every respect, It is also hugely noted that he suffers from enormous hegemonial traits.
He doesn't care a lot for others, as seen when he shot the stocky kid on the bridge, or letting Achilleus fight to the death, as long as he could accomplish his own objectives. He was also quite delusional, as he thought that the shambling Royal Family could actually help him rule London. David pompously expected people to do as he said, and cared incredibly about his image, shown during the duel between Achilleus and John, he begins to make a speech and acts with childish protestation when the fight begins before he can even get started.
Though he has a lot of bad qualities, he had a certain degree of determination, independence, confidence and charisma, and got his kids to follow him everywhere he went. He bears a similarity to Jordan, thinking that organisation was the key to survival. That being said, he is charismatic in that his sheer confidence alarms everyone around him, whilst Jordan is bluntly callous and cold with no attempt to conceal these traits at all.
He was, acceptably, highly intelligent and able to deduce a tactical plan to take over London, and his cleverness and cerebrality when Ollie mentioned that he was also quite clever. He was manipulative and Machiavellian, able to lead others to join him, even members of the Waitrose gang. But this backfired on him when people started to realize just how insane and diabolical he was.
David was possibly a psychopathic person, shown when he deliberately shot a boy dead simply for disagreeing with him. He also constantly lost his temper when things did not go his way or if people assumed correct things about him that he simply didn't believe.
David had an excellent sense of style: He dressed smartly, almost extravagantly and with a lack of self-consciousness, first seen in a black tuxedo. He also likes to think of himself as the Lord Chamberlain, also indicating his megalomania and obsession with gaining powers simply by thinking of himself as the superior individual. His self-control and poise had limits, since he reacted violently when it was implied that he was crazy, but this only supported the idea that he was
Fate
In The End Immediately after Paul's death sickos begin to swarm David and his group in Hyde Park. His soldiers try to fend them off but to no avail. David groups up with Jester as they are both surrounded. David starts to question whether what he did to get to the top was worth it. David begins to sob as he wishes his mom was there to comfort him and tell him she loved him. Jester hugs David tightly as they are both swarmed and devoured by the oncoming horde of sickos.
His last words were, "We're just kids. How could we be expected to make the right decisions?"