Waller

Gunnery Sergeant Waller was a UNSC Marine and ODST. Waller was one of the soldiers stationed aboard the Pillar of Autumn as part of First Lieutenant Melissa McKay's unit. He made the jump to Installation 04 along with the rest of his unit when the ship crashed after being attacked by the Covenant.

Presumably, he was part of the attack that took Alpha Base and later part of the convoy McKay made to transport supplies from the Autumn.

He was the ODST in charge during the amphibious assault on The Silent Cartographer. He and his men came under heavy Covenant attack as soon as the Master Chief left them outside the Silent Cartographer, and they were shot down, having failed to take cover. However someway that he survived and he was part of the second squad finding the casche, the sergeant in 343 Guilty Spark can be either Waller or Johnson. It is unknown weather he is alive and made it to fight on Earth like Stacker and Dubbo.

Trivia

 * Waller's single appearance is in Halo: The Flood, whereas in the game his role is filled by Sergeant Stacker.