- "I am 49 Gradual Insanity, Monitor of Installation 03, and caretaker of these Sentinels. You're ancestors left me with this dry, barren, landscape."
- ―49 Gradual Insanity, meeting James Gray, the newest reclaimer.
49 Gradual Insanity is the Monitor and caretaker of Installation 03. He fought in numerous Forerunner-Flood Wars, virtually invincible due to his power, and the fact that he is not a living organism. He was named due to the fact he would often go rampant when annoyed or angered, and the Forerunner thought he was slowly becoming insane, hence the term Gradual Insanity. When the Forerunner were destroyed, 49GI went rampant, and stayed that way for a month, when he regained his senses, 49 saw that the Forerunners had handed down their legacy, for Humans, on Earth, to be Reclaimers.
When the Forerunner-Flood War was underway, Installation 03 was under construction, Installation 03 would have fired faster than any of the other Installations, due to the monitor, 49 Gradual Insanity's stubbornness. A premature fire would damage the entire array, and the Forerunner protecting it. 49 took part in activating the rings later on, and took part in a small battle near the end of the Forerunner-Flood War.