"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."
"Reaper? A label created by the Protheans to give voice to their destruction. In the end, what they chose to call us is irrelevant, we simply are."
"Organic life is nothing but a genetic mutation, an accident. Your lives are measured in years and decades. You wither, and die. We are eternal, the pinnacle of evolution and existence. Before us, you are nothing. Your extinction is inevitable. We are the end of everything."
"The pattern has repeated itself more times than you can fathom. Organic civilisations rise, evolve, advance, then at the apex of their glory, they are extinguished. The Protheans were not the first, they did not create the citadel, they did not forge the mass relays, they merely found them, the legacy of my kind."
"Your civilization is based on the technology of the mass relays, our technology. By using it, your society develops along the paths we desire. We impose order on the chaos of organic evolution. 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."
"I am Sovereign. And this station is MINE!"
(Basically, everything Sovereign ever says)
Other:
Krogan Warlord: Surrender... or don't. That would be more fun.
Inamorda: If you don't stop poking me, I'll throw you off that balcony.