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During the Red Legion's occupation of The Last City, Mattox and his longtime friend Lyria Graemer identified where in the Tower the Speaker was being held by Dominus Ghaul and decided to launch a rescue mission. While scaling the Tower, their progress was halted by Cabal forces on the ground, who Lyria began firing back at while Mattox continued his climb. When he reached her position he began to make a joke, but was shot in the head and killed instantly. Before his body could fall, Lyria caught the lifeless Exo and knowing that she would not survive, decided to end the mission together with Mattox by loading his rocket launcher full of grenades and turning themselves into an improvised projectile to neutralize their attackers below.
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