Ellis was a soldier at Camp Humphreys under Speke and the first person Gerry Lane meets who is ignored by Zeke.
At an unkown point Ellis was transferred to Camp Humphreys. Prior to the outbreak he crippled his leg leaving him with an obvious limp.
When the outbreak occurred at the base Ellis was part of the detail that attempted to restrain the infected base doctor. The base doctor managed to bite several people starting an outbreak. Elis was trapped in a holding cell with several infected who curiously ignored him; allowing him to escape the cell and incinerate them; therby securing the inside of the building. His fellow soldiers considered him very lucky to have survived the close quarters battle.
He is present when Speke is bitten and offers to execute him from his sniper perch on the roof.
Gerry later realizes that Ellis and several others were ignored by the zombies due to illness and serious injury. Ellis' crippled leg making him unsuitable to be infected.