From Halopedia, the Halo wiki
Ryder Hannigan is a human who listened to Benjamin Giraud's Hunt the Truth audio journal in 2558. After Giraud's entries claimed that the Master Chief's origins were not so heroic as claimed, Hannigan mailed Giraud an audio email where he angrily claimed Giraud was an attention-seeking liar. He demanded Giraud leave the Master Chief alone and appreciate how he had single-handedly saved humanity from extinction.
List of appearances