At one point in his life, Mike was a part of the Spartan-II project. During the project, he developed a romantic relationship with Professor Agnes. Together they had a little girl who, for unexplained reasons, died. Sometime afterwards, he and Agnes broke up. Both he and Agnes knew elements of the Spartan program that were done that Halsey didn't even know about. Like Halsey, he feels regret for what was done to the Spartan candidates. When Ralph-103 and Daisy-023 died, he wrote a letter to Agnes explaining that she needs to think about him and other elements when working on "new children."
- News of the UNSC Spirit of Fire's encounter with the Flood may have reached ONI by unknown means. Mike and Agnes may have had high enough clearance to know about the Flood. In a letter from Mike to Agnes, Mike mentions the "Flood" anomaly as a path of least resistance than to abandon his own human worth.