Kappus

"It looks like the Covenant worked pretty hard to lock it down."

- Private Kappus, before unknowingly releasing the Flood.

Kappus was a United Nations Space Command Marine technical specialist.

He was featured in Halo: Combat Evolved as part of the squad that also housed Privates Manuel Mendoza, Bisenti, Riley, Private First Class Jenkins, and Staff Sergeant Avery Johnson.

He was a Tech Specialist in Covenant, Forerunner, and UNSC technology. One of his tasks was opening locked doors. He was ordered by Captain Jacob Keyes to open the door that just so happened to be the only thing holding back the Flood. Unwillingly and unknowingly, Kappus unleashed the Flood on Installation 04, dooming him and the rest of his squad, save for Johnson. When Riley was attacked by Infection Form, Kappus successfully managed to pull it off, but others soon found Riley. Kappus was one of the first to be transformed into a human Combat Form.

Private Kappus was probably killed by the Master Chief during the latter's escape from the installation, by the UNSC Marine or Covenant forces, or when the Chief destroyed Halo.

Trivia

 * His role in the game is often mistaken for that of Mendoza's due to the same character model seen in-game.
 * It is possible Kappus was the Marine that fell through the door when the Chief arrived at the structure.