Joe Berger

Private First Class Joe Berger was an enlisted member of the UNSC Marine Corps who participated in the Human-Covenant War. In 2545 he was stationed aboard the destroyer Kronstadt. 
Berger greatly admired the Orbital Drop Shock Troopers. During his stay aboard the Kronstadt, he tried to sit near a team of these operators in the ship's mess hall, attempting to eavesdrop on their conversation, before being pulled away by a fellow Marine. Being an admirer of the ODSTs, he also held an evident disregard for the SPARTAN-II program, whom the ODSTs shared a bitter rivalry with.
After the same team arrived back from a mission on Heian, he sat by them and gave them some apples, commenting on Cal-141's lack of combat skills down on the planet, leading to her death. While they had previously despised the SPARTAN program, the Helljumpers were angered by Berger's disrespect for Cal's sacrifice, scolding him for what he said and throwing the apples back in his face.
It is unknown how Berger was aware of Cal-141's death, as Directive 930 requires the falsification of any circumstances regarding the deaths of Spartans.