How we cite our quotes: (Book.Chapter.Paragraph)
Quote #1
"[…] Vortimer is raising troops of his own. They say he would like to be High King, and that Vortigern looks like having a rebellion on his hands when he can least afford it. The Queen's much hated, you know that; Vortimer's mother was good British, and besides, young men want a young king." (I.10.11)
Young Merlin gets a political lesson from Galapas here. Vortimer is Vortigern's son (by his first wife), and he's none too pleased by his father's actions. This new rebellion concerns Merlin's family, since his Uncle Camlach would like to join young Vortimer to overthrow the High King. That ambition will be Camlach's downfall, though Merlin can't know that at this time.
Quote #2
"Whose blood did you think?' he asked, still with that lifted lip. "Deer's blood, that's all. When the message came, we had just killed. I was twelve miles off, I and my men." He stared at them, as if daring them to comment. (I.10.39)
Camlach has just reached the bedside of his dead father, who was the King of South Wales. The implication here is that the blood on Camlach's dagger might be the king's. The major question is this: how badly does Camlach want to be king? It's clear that he's willing to kill for it (he'll totally try to kill Merlin to secure his inheritance). But it's never really established that Camlach had a direct hand in the death of his father.
Quote #3
[…] I heard countless stories of his prowess at arms and how he had sworn to be avenged on Vortigern for the killing of his cousin Constantius, even though it would take a lifetime. This, in fact, it threatened to do, for it seemed an almost impossible task for so poor a country to raise the kind of army that might defeat Vortigern and the Saxons, and gain a footing in Greater Britain. (II.6.27)
Merlin is talking about King Budec I, sovereign of Brittany. He entertains the idea that Budec really will raise an army after all, especially since Vortigern is having a really hard time containing the Saxons at the moment. But it isn't the motivations of Budec that Vortigern needs to worry about, as it turns out. It's Ambrosius and Uther, brothers of the murdered Constantius, who have the real ax to grind.