From Halopedia, the Halo wiki
Aden Langereis was a human who listened to Benjamin Giraud's Hunt the Truth audio journal in 2558. After Giraud's entries suggested there were dark secrets being withheld about the Master Chief, Langereis mailed Giraud an audio email where he gave his support for the journalist's efforts. He claimed that Giraud had gotten him curious about the matter despite the Chief's reputation, and urged him to continue the audio journal and stay safe while doing so.
List of appearances