21st Marine Division

The 9th Marine Expeditionary Force, twenty-first division, 1st battalion ("M-EDF 9/21/1") was a UNSC Marine Corps unit, consisting of brave and experienced men, that was one of many units serving in the Epsilon Eridanus System. This unit was a critical part of the UNSC's fight against the Insurrection.

LtCol Ponder, at that time, was a member of the unit, and lost his arm in Elysium City, Eridanus II, in a failed attempt to obtain information from an Insurrectionist who had married the daughter of one of the local officials. When this local official was questioned about Colonel Robert Watts' second in command, he looked LtCol Ponder in the eye and said: "Someday we will win. No matter what it takes." The man then grabbed his own daughter and held up a grenade. Ponder knew that the man was bluffing; that although he was deticated to the Insurrectionist cause, he wouldn't be willing to kill his whole family. One of Ponder's snipers thought that the man really was going to pull the pin and shot through the wall of the house, which "tore the guy in half." On reflex, the man pulled the pin. The resulting explosion took off Ponder's arm. After the incident, Ponder believed that the top brass wanted him to "take an early retirement," but instead, stayed in the military. The incident caused his taking a two-step drop in rank to Captain.