These are my favorite quotes. They can be from anywhere.
"I never cared about justice, and I don't recall ever calling myself a hero... I have always only fought for the people I believe in. I won't hesitate... If an enemy appears in front of me, I will destroy it!" - Zero, from Megaman Zero 4.
"I'll teach you there is no place for fools to hide! Fools must live under my rule and my rule alone, thanks to Ragnarok!" - Dr Weil, from Megaman Zero 4.
"Rend your foes asunder with a spear of light!" - Daybreak's tooltip
"Live out an eternity of suffering, fool! I will be the first entry in a glorious new history! Remember the name Dr. Weil! The world, everything, mine... Forever!!"
- Dr Weil, from Mega Man Zero 4 (SPOILER ALERT) if he kills Zero
" I gave you life, and yet you defy me? So be it! You shall pay for your ingratitude with relentless pain!"
- Devil Doom, from Shadow the Hedgehog.
"Even if we Reploids are destined to join the scrap heap when that evolutionary step does come about... we still have to fight... not only against Mavericks, but against our own destiny as well."
- Zero, in Mega Man X8.
"Let your mind be the door to your goals.
And your heart shall be your guiding key."
- unknown
"The most important thing right now is the restoration of the earth...I don't have time for you...If you appear in front of me again, I'll kill you...that's it."
- Mega Man X, in Mega Man X6.