Diane is a member of the Resistance movement at Outer Heaven. She was formerly a vocalist of Thin Wall, a positive punk band and uses her feminity for intelligence activities. Having gone on several intelligence missions in Outer Heaven, she has accumulated knowledge about the mercenaries and armaments of Outer Heaven. During Operation Intrude N313, she provided her expertise to Solid Snake, providing with the weaknesses of each of Outer Heaven's mercenaries.
