From Halopedia, the Halo wiki
Major Sedavian was an Orbital Drop Shock Trooper who commanded the ODST contingent that took part in the Battle of Hat Yai. The battle saw the first combat between ODSTs and Covenant forces. However, Sedavian himself was not a participant for most of the battle, since his SOEIV landed far from most of the ODSTs, and he did not meet up with the ODSTs until the battle was almost over. Thus, Rahud was forced to take command of the ODST forces.
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