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.
Quote #4
"I don't see myself as a king. Half a king, perhaps, or more likely a quarter—the little bit that sees and thinks, but can't do. Perhaps Uther and I between us might make one, if you go? He's larger than life already, wouldn't you say?" (II.12.79)
Merlin tries to reassure his dad that he has no desire to be High King of Britain. For a minute, Ambrosius has heart failure: he's so glad to have his son around, but that means there will be problems with Uther, who really does want to be the next king. Merlin's humility and strong sense of purpose keep him out of an inheritance squabble with one of the strongest soldiers in the kingdom. That's good politics.
Quote #5
"I cannot yet afford to throw aside valuable tools because I don't like their design," he said. "He is useful, so I use him. You will do the same, if you are wise." (II.12.88)
Ambrosius is not only ambitious—he's also straight up clever. He teaches young Merlin to use people for what they're worth. In this case, he's talking about the wicked Belasius. Sure, he's a shady dude who sacrifices people just because he feels like it, but he's also smart, and he has a kind of power himself. Ambrosius wants Merlin to understand that you don't have approve of people or even like them to learn something valuable from them.
Quote #6
The enemy was at the gates, and what Vortigern needed now was not logic and an engineer; he wanted magic, and something—anything—that promised quick safety, and kept his followers loyal. (III.10.37)
At this point in the game, Vortigern's only ambition is to live one more day. Merlin reads the situation correctly and knows that he has to give the panicky king a little hocus pocus to settle him down—and that's exactly what he does. Instead of giving him an engineer's explanation for why his tower walls won't stand, Merlin goes the supernatural route. He throws in a dire prophecy for free.
Quote #7
She was crossing herself, her eyes at once startled and severe, and through it all afraid. "Merlin—" but on the word a cough shook her, so that when she managed to speak again it was only a harsh whisper: "Beware of arrogance. Even if God has given you power—" (IV.3.20)
Niniane is a good Christian, which means that she's particularly appalled at the deadly sin of pride. She's pretty sure that Merlin's heading for hellfire when he starts to talk about how powerful his supernatural abilities are. But Merlin—ever the dutiful son—reassures her that he has no personal pride or serious ambitions. He just misspoke.
Quote #8
"You cannot serve me as you served my brother. You must know that. I want none of your prophecies. My brother was wrong when he said that we would work together for Britain. Our stars will not conjoin." (V.2.27)
Uther clearly has his own agenda, and he's not worried about alienating his own flesh and blood to fulfill it. There's no love lost here: Merlin doesn't particularly want to serve Uther and has no sense of allegiance to him. Merlin now has his own ambitions, which only partly depend on his uncle.
Quote #9
"I was married at sixteen to the Lord of Cornwall; he is a good man; I honour and respect him. Until I came to London I was half content to starve and die there in Cornwall, but he brought me here, and now it has happened. Now I know what I must have, but it is beyond me to have it, beyond the wife of Gorlois of Cornwall." (V.5.32)
Ygraine is in a serious dilemma. Up until now, she's been content with her honorable life as Duchess of Cornwall, even though her husband is old enough to be her grandpa. Now, she's the object of King Uther's lust, and she can't stand the temptation. It turns out that she has unfulfilled wishes of her own—and she'll need Merlin's help to achieve them.
Quote #10
"I see now what your magic is, this 'power' you talk of. […] It is nothing but human trickery, an attempt at statecraft which my brother taught you to like and to play for and to believe was your mystery. It is trickery to promise men what they desire, to let them think you have the power to give it, but to keep the price secret, and then leave them to pay." (V.10.25)
Uther is pretty miffed that his night of lovin' with Ygraine has turned into an enormous disaster. This was not what Merlin promised when he said he could arrange the hookup. But Merlin doesn't really care about Uther's opinions at this point. Is Merlin really playing a political game here? To some extent, yes. He's working with supernatural powers to bring about the birth of the super king, Arthur. But Merlin acknowledges that he, like Uther, is nothing but a tool in the cabinet of the gods.