From Halopedia, the Halo wiki
In 2555, Kapalos, along with 9 other Marines, was selected by Annabelle Richards to accompany her to Installation 00 in order to stop the Halos from activating. Kapalos was on the ship when N'tho 'Sraom decided to go through the portal without consulting with the UNSC. Kapalos survived the attack by Retriever Sentinels and the subsequent crash landing. Sometime after setting out towards the Citadel they were attacked by chaefkas and morolaaths. Kapalos along with Gonzalez and Turot were killed by the creatures.
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