Echo Six
From Halopedia, the Halo wiki
Echo Six was a codename for an ODST stationed in Gyeonggi-do, to help in testing the MJOLNIR Mark VI armor.
Spartan-062 (Maria) tested the MJOLNIR Mark VI in a armor testing exercise with several ODSTs. During the armor testing, Spartan-062 hurls a paintball grenade onto the middle of the unsuspecting "Helljumpers", neutralizing Echo 1 through 5. The sole survivor of the blast, Echo 6, ran but later on gunned down by Spartan-062, but not before initiating the "Bulgoki Gambit". After Spartan-062 was subdued, she was brought back to the Special Ops Center, accompanied by him and his ODST companions (whom all had paintball marks on them).