From Halopedia, the Halo wiki
In 2531, he was present for the Battle of Arcadia and the Battle of Trove. Following these events, he and the rest of the crew aboard the ship entered cryostasis, having sacrificed the ship's slipspace drive to destroy Trove. In 2559, he and the others were awakened to find themselves above the Banished-controlled Installation 00. During the battle to retake the Ark, Sergeant Allieri participated in an operation that helped bring down the assault carrier Enduring Conviction. Soon after Professor Ellen Anders deactivated the Enduring Conviction's shields with a particle cannon, Sergeant Allieri's and Jerome-092's pelicans were shot down by anti-aircraft units as they approached the vessel's gravity lift. He and three of his men survived the crash and quickly sought to rendezvous with Jerome-092 in order to take on new orders. On their way to find the Spartan, they elimated Banished infantry and cloaked plasma mines. After regrouping, they then proceeded to secure a zone for reinforcing Kodiaks in order to clear the grav lift.
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