Walpole

Private Walpole was a UNSC Marine Shock Trooper under the command of Gunnery Sergeant Pete Stacker, and was assigned to the 7th Battalion, 105th ODST Division in 2552.

First Battle of Earth
His unit, second squad, 7th Battalion of the 105th Shock Division, fought during the Battle of Earth, and subsequently, during the First Battle of Mombasa in October 2552.

Pelican down
During the battle, he and his squad were in Stacker's D77-TC Pelican dropship when it was shot down by a Covenant Scarab Walker on approach to an area in New Mombasa, Kenya.

After their Pelican made a rough landing outside of an abandoned beachside hotel, Walpole reported that O'Brian was killed on impact. He, along with his squad quickly moved out to get better cover, and headed toward Hotel Zanzibar in Old Mombasa.

Moments later, a Plasma grenade had landed on Walpole's helmet. Using quick reflexes, the ODST was able to remove his headgear and hurl it toward a camouflaged  Special ops Sangheili's position on higher ground.

There, Sergeant Stacker and his team saw the charging soldier, only after it had held Jones as a prisoner. Butkis opened fire with an overcharged Plasma Pistol at the Sangheili, as Stacker shot the Elite in the head with his BR55 Battle Rifle. It is assumed Walpole had returned to In Amber Clad with Stacker after the Chief destroyed the Scarab.