“You are not Garrosh Hellscream, why do you want to throw the Horde into the meat grinder again?
Sylvanas’s eyes did not waver, even in the face of his rage. "If I dedicated myself to peace with the Alliance, would it last a year?”
“Yes,” Saurfang said curtly.
“How about two years? Five? Ten? Fifty?”
Saurfang felt the trap closing in on him, and he did not like it. “We fought side-by-side against the Burning Legion. That creates bonds that are not easily broken.
"Time breaks every bond.” Sylvanas leaned across the table. Her words flew like arrows. “What do you believe? Will peace last five years or fifty?”
He leaned forward, too, his face inches away from hers. Neither blinked. “What I believe doesn’t matter, Warchief. What do you believe?”
“I believe the exiles of Gilneas will never forgive the Horde for driving them away. I believe the living humans of Lordaeron think it is blasphemy that my people still hold their city. I believe the ancient divide between our allies in Silvermoon and their kin in Darnassus is not easily mended.” There was a smile on Sylvanas’ face. It was not a pleasant one.
“I believe the Darkspear tribe hasn’t forgotten who drove them from their islands,” she continued. “I believe every orc your age remembers being imprisoned for years in filthy camps, wallowing in despair and surviving on human scraps. I believe every human remembers the tales of the terrible Horde that caused so much destruction in its first invasion, and I believe they blame every orc for that, no matter what you people have done to redeem yourselves. And I remember very well that my first Forsaken were once loyal Alliance citizens. We died for that banner, and our reward was to be hunted as vermin. I believe that there will be no permanent peace with the Alliance – not unless we win it on the battlefield on our terms. And believing that, answer this, Saurfang: what use is delaying the inevitable? ”
“The boy in Stormwind will not start a war tomorrow,” Saurfang said.
Her eyebrows lowered. “With Genn Greymane in his ear? We will see. ”
That was a concern, Saurfang had to concede. In the thick of fighting against the Burning Legion, Greymane had launched a mission to kill Sylvanas. It had gotten some of Stormwind’s few remaining airships destroyed.
There were whispers that Greymane had ordered the attack without Anduin’s permission, but as far as Saurfang knew, Greymane had not been punished. The implications of that were troubling, and every possible explanation led to the same conclusion: the old Worgen would always drive the Alliance toward war against the Horde.
Sylvanas’ eyes glittered. “And the boy is becoming a man. What if that man decides that he has no choice but to launch war on us?”
So this actually shows that Sylvanas actually has reasons and a plan – none of which was shown to us in-game.
Her conclusion is questionable, but the logic she has is something you can make sense of. She doesn’t believe peace matters if it’s just going to war with the Alliance anyway. What is the purpose of, say, 5 years of peace? To her, that’s 5 years of the Alliance able to gather Azerite. To her, that’s 5 years of Genn whispering into Anduin’s ears constantly, “The Horde must be destroyed.” It makes sense to me. It feels like an honest argument. It’s certainly not the first time someone’s brought up the idea of being able to overwhelm your enemy with a powerful first strike. Her argument about Genn and Stormheim feels especially on point – he’s shown he will strike at the Forsaken and Horde if given the chance and without orders even if the end of the world is at their doorstep.
Nobbel also makes this remark, though it’s not text lifted directly from the novellas:
But since Saurfang refused to kill him, she had to do something else and at that moment decided to give the other. Saurfang screams for them to stop firing, this is not their way, this is not what he signed up for, but it was already too late.
So basically since Saurfang didn’t kill Malfurion, Sylvanas makes a change of plans on the spot. She still believes she must crush Teldrassil and destroy the Alliance’s hope and create infighting within them. Burning Teldrassil is the result. It’s even noted: Saurfang attempts to stop them but cannot.
She even makes sure to rub it into Saurfang’s face:
“This was your victory. None of this–not this battle, not Malfurion’s defeat–would have happened without you. You have earned this honor. Take a moment, if you’d like, and then take his head. I will meet you in Darkshore.”
And with that, she disappeared over a rise to the north.
Saurfang felt numb. You have earned this honor.
This is interesting to me because she’s basically laying the “victory” at Saurfang’s feet. Basically gaslighting the guy and throwing his saving of Malfurion in his face. ‘Congrats Saurfang, you saved one night elf and killed thousands more in the process.’
To which Saurfang has this moment (not sure if before or after the last bit):
The screams continued. They reminded him of Shattrath. He had loved the sound, then.
Smoke filled the air, reminding him of Stormwind, of racing through the streets as buildings burned all around him, finding cowering humans and butchering them as they begged for their lives. He had loved the slaughter, then.
And he had loved this war too, hadn’t he?
Saurfang did not move for hours, not until the screams faded and the flames had burned themselves down to embers. Before him, stood a smoking husk that had once been a great civilization. Inside him was a feeling of despair, a feeling of shame. There was no haze of corruption now to soften the horror.
Saurfang would remember this moment in his dreams forever. He would relive his shame, and all the new ones to come, over and over again.
You have led your Horde in the service of death, Malfurion had said.
How could Saurfang face the soldiers he had led into this war? How could he explain what they had done?
He couldn’t. He would never know how.
But the burden would be his, always, until his dying day.
As Saurfang turned away, he hoped that day would come soon…
So now we know why he’s so readily suicidal at the Siege of Lordaeron and why he starts to defy Sylvanas, as well. The guy carries the weight of Teldrassil’s dead on his shoulders while Sylvanas casually shrugs it off as the price of war.
So there you go. Some key details left out of in-game on Sylvana’s motivations and reasonings, plus a little extra on Saurfang.