Prisoner of war
From Halopedia, the Halo wiki
A prisoner of war (POW, PoW, or PW) is a combatant who is imprisoned by an enemy force during or immediately after an armed conflict.
Even in the 26th Century, the UNSC continues to take prisoners of war in their conflict against the Covenant, often using them as manual labor to construct fortifications for defending against Covenant attack and digging graves for Covenant and UNSC dead. In general, however, UNSC Marines appear to maintain a "policy" of leaving no Covenant alive. After the destruction of Alpha Halo, multiple Sangheili were recovered in their lifepods by a UNSC-requisitioned prison ship, the Mona Lisa and experimented on by an Office of Naval Intelligence medical officer seeking ways to harness the Flood, either to find a "cure" or to use it as a weapon against the Covenant. The last survivor of these, "Henry", assisted the other human prisoners on the ship and was one of only two survivors, with him and Patrick Rimmer joining a UNSC Marine squad to try and escape. For much of the war, the Covenant refused to take prisoners, executing any human personnel who were captured or who surrendered. After the discovery that only human "Reclaimers" could activate Forerunner artifacts, the Covenant kept them alive for such a purpose. After the ascension of the Jiralhanae to the positions formerly held by the Sangheili, UNSC PoWs were routinely captured and butchered for food for the Jiralhanae.
PoWs in the Halo games
Though the Covenant have repeatedly been stated to never take prisoners, the games depict UNSC captives in Covenant custody multiple times.
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