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Captain Zelos Cuvier was an ODST commissioned officer of the United Nations Space Command. He commanded First Platoon Alpha Company of the 21st Space Assault Battalion during the Insurrection and the opening months of the Human-Covenant War.
Operation: SILENT STORM
In early 2526, the 21st Space Assault Battalion—also known as the Black Daggers—were selected to join Task Force Yama as part of a daring new plan devised by Admirals Preston Cole, Michael Stanforth and Doctor Catherine Halsey to combat the emerging Covenant threat. Following the success of previous boarding actions taken against the vessels Minor Transgression and Unrelenting, it was determined that similar tactics were likely to yield greater success rates against the technologically superior and much larger Covenant fleet. With the Black Daggers' experience in space assault operations during the Insurrection, they were chosen to join the task force to aid the assigned SPARTAN-IIs in boarding and planting nuclear weapons aboard Covenant warships, buying the UNSC time to prepare for future fleet actions 
Battle of Seoba
In preparation for their first attack, an ice quarry on the moon of Seoba was selected as a staging ground, due to its host planet Biko laying in the projected path of the Covenant. Upon arriving in the system, Task Force Yama discovered an Insurrectionist base set up in the designated quarry. The Black Daggers and SPARTANs were authorized to engage and eliminate the insurgents to ensure Operation: SILENT STORM could go ahead as planned. John-117 took the initiative, disobeying orders and diving out of their prowler to cover the ODSTs as they deployed under fire. During this engagement, Ghost Flight had managed to damage the insurrectionists' communications outpost, ensuring that the rebels couldn't call for reinforcements and reveal the secret UNSC operation. However, a convoy of armored Civets was slowly making its way up the frozen mountain to repair the array, and it was Alpha Company's job to stop them.
When Cuvier regrouped on the ground with Blue Team and Lieutenant Nelly Hamm, he commended Hamm as he thought that it had been her idea to deploy the Spartans first. She then suggested that the Spartans overtake and destroy the Civets by travelling up the inside of the abandoned mass driver that dominated the area. Cuvier signed off on the plan. He was however, unfortunately killed in the ensuing battle which directly resulted in the promotion of then Lieutenant Nelly Hamm to the rank of Captain and filling his role as Captain of First Platoon Alpha Company, much to the dismay of John-117.
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