Even if the person/machine/thing saying them is good or righteous or even the player-character. This thread is about particular phrases that they may utter, which turn your blood to ice, or ignite a fire in your heart upon hearing them.
Pious Augustus, from Eternal Darkness: Sanity's Requiem
"I am the scourge of God, appointed to chastise you, since no one knows the remedy for your iniquity except me. You are wicked, but I am more wicked than you."
Jon Irenicus, from Baldur's Gate II: Shadows of Amn
"Silence, dog. Your only purpose is to die by my hand."
"Your actions affect so many others than yourself. You will come to realize what little choice you have. You will do what you must, become what you must, or others will pay for your cowardice. You WILL accept the gifts offered to you."
"Life... is strength. That is not to be contested; it seems logical enough. You live; you affect your world. But is it what you want? You are... different inside. This woman lives and has strength of a sort. She lost her parents to plague, her husband to war, but she persevered. Her farm prospered, her children are well-fed, and her name respected throughout her land. She lived as she thought she should. And now she is dead. Her land will be divided, her children will move on, and she will be forgotten. She lived a good life, but she had no real power; she was a slave to death. I wonder if you are destined to be forgotten as she was. Will your life fade in the shadow of greater beings?"
"I... I do not remember your love, Ellesime. I have tried to. I have tried to recreate it, to spark it anew in my memory. But it is gone... a hollow, dead thing. For years, I clung to the memory of it. Then the memory of the memory. And then nothing. The Seldarine took that from me, too. I look upon you and I feel nothing. I remember nothing but you turning your back on me, along with all the others. Once my thirst for power was everything. And now I hunger only for revenge. And... I... Will... HAVE IT!!"
AM, from I Have No Mouth, and I Must Scream
"Hate. Let me tell you how much I've come to hate you since I began to live. There are 387.44 million miles of printed circuits in wafer thin layers that fill my complex. If the word 'hate' was engraved on each nanoangstrom of those hundreds of miles it would not equal one one-billionth of the hate I feel for humans at this micro-instant. For you. Hate. HATE."
"Ellen! So think, think about the yellow box, Ellen! Remember the pain? Remember the many caverns in which you felt the pain? Now, now, don't start to cry, it's only pain. Tsk, tsk, tsk. That's such a sexist stereotype. Just remember the pain, Ellen, and think about how to end it, Ellen, to survive here in the center of my beating heart, my hungry belly, my tightened bowels."
Andrew Ryan, from BioShock
"I am Andrew Ryan, and I'm here to ask you a question. Is a man not entitled to the sweat of his brow? 'No!' says the man in Washington, 'It belongs to the poor.' 'No!' says the man in the Vatican, 'It belongs to God.' 'No!' says the man in Moscow, 'It belongs to everyone.' I rejected those answers; instead, I chose something different. I chose the impossible. I chose... Rapture, a city where the artist would not fear the censor, where the scientist would not be bound by petty morality, Where the great would not be constrained by the small! And with the sweat of your brow, Rapture can become your city as well."
Dr. Wallace Breen, from Half-Life 2: Episode One
"Tell me, Dr. Freeman, if you can. You have destroyed so much. What is it, exactly, that you have created? Can you name even one thing? I thought not."
Kain, from Blood Omen: Legacy of Kain
"I am the last Pillar. The only survivor of the Circle of Nine. At my whim the world will be healed or damned. At my whim."
"Vae Victus -- suffering to the conquered. Ironic that now I was the one suffering. Not anything as pedestrian as physical pain. Rather the cruel jab of impotent anger -- the hunger for revenge. I didn't care if I was in Heaven or Hell -- all I wanted was to kill my assassins. Sometimes you get what you wish for. The Necromancer Mortanius offered me a chance for vengeance. And like a fool, I jumped at his offer without considering the cost. Nothing is free, not even revenge."
"The world had changed to my eyes. I had not expected such cruelty from the light. For in the embrace of the sun, I could find no comfort, only malice. This would change in time for the worse, along with other things."
Sovereign, from Mass Effect
Rudimentary creatures of blood and flesh, you touch my mind, fumbling in ignorance, incapable of understanding.
There is a realm of existence so far beyond your own you cannot even imagine it. I am beyond your comprehension. I am Sovereign.
Your civilization is based on the technology of the mass relays. Our technology. By using it, your civilization develops along the paths we desire. We impose order on the chaos of organic life. You exist because we allow it, and you will end because we demand it.
We have no beginning. We have no end. We are infinite. Millions of years after your civilization has been eradicated and forgotten, we will endure.
We are legion. The time of our return is coming. Our numbers will darken the sky of every world. You cannot escape your doom.
Your words are as empty as your future. I am the Vanguard of your destruction. This exchange is over...