These soldiers, in an alternate timeline, boarded Enterprise twice in order to destroy what was left of the Human race. As Jonathan Archer, T'Pol, and Phlox worked at the warp core to set up a catastrophic subspace implosion to restore the timeline, the Xindi soldiers killed Phlox and T'Pol. Archer was also shot but managed to initiate the subspace implosion before he died and thereby restored the timeline. (ENT: "Twilight")
