
L: I'm close to finishing the task. The indexing and the archival processes are as complete as I can hope for. If we wait longer, we risk catastrophe. The thing has already destroyed every colony on my side of the line.
Please. Activate the Array.
D: No. Activation is murder. A genocide larger than [this galaxy] has ever known. We are sworn to protect life not destroy it! That is the Mantle we were given to carry.
L: The Mantle. You still hold to that [fairy tale] after all that has happened? After this thing has consumed a million worlds?
Can't you see? Belief in the Mantle sealed our doom! Weakened our [protectorates], bred dependence and sloth. Our [so-called Guardianship] has stripped those we would keep safe of any capacity for self-defense!
Were we such noble [Guardians] when we drew our line and abandoned billions to the parasite?
D: The Mantle has not failed! I've already razed scores of worlds--sterilized systems, routed and [disintegrated] the parasite! We're learning its tricks and strategies. We can halt this thing! And we can follow in Their footsteps!
There are no unstoppable forces in this universe. There are no immovable objects. Everything gives if you push hard enough.
L: And what about us, Didact? We've been irresistible and immovable for too long. Maybe it's our turn to give.
//FRAGMENT ENDS
This passage comes from a node off the surface of the Ark during the events of Halo 3. It shows that the Forerunners had become too comfortable and content with their galatic dominance and weren't prepared to defend themselves against the Flood. It inevitably led to their downfall.
Halo, the Flood, and all other names are owned by Microsoft and Bungie Studios. This is just a fan site! :)