Corporal Lee "Dash" Dashiel was a demolitions expert who helped Sgt. Nathan Hale and Pvt. Jimmy Sanchez find the only inhibitor which was crucial for the Sentinels' survival.

Cpl. Dashiel first appears in St. Paul, Minnesota where the Chimera have taken over half of the city. An officer appears to him and tells him to report immediately to an installation in Keystone, South Dakota. Dashiel replies "Just a sec" and then presses down on a explosives plunger which in turn destroys a bridge killing and preventing the Chimera from crossing to the Army's position.

Dashiel turns up in the installation and meets Pvt. Sanchez and Hale. The latter tells Dashiel and Sanchez that he specifically requested them only for Sanchez to interrupt and annoy Hale and Dashiel by saying that the mission was suicide until after Hale had a persuasive talk with Sanchez, they set off to Salinas, California.

While in Salinas Sanchez continues his distrust towards Hale as a "Stink" to which Dashiel, who is sick of arguing, replies "Part Stink". Sanchez countered that all people who go on missions with Sentinels die in which Dashiel proves him wrong by saying "Hale ain't like that. This is my third mission with the Sarge, and I trust him with my life". Hale then says that the Chimera were there to which Sanchez seeing the place deserted disagrees whilst Dashiel, who is a good friend of Hale, says "If he says there here, there here. He can see into his mind sometimes." Indeed, a Chimeran ambush awaited the three.

After defeating Hybrids and Grey Jacks, the three follow some Grims and Carriers to a conversion center. After entering the conversion center through a sewage pipe they find a room full of spinner pods. Hale opens one to find Dr. Silbermann who tells him to get the inhibitor and then kill him. Just as they are about to they are attacked by Spinners who manage to infect Sanchez and mortally wounded Dashiel. After Sanchez begged to be mercifully killed by Hale, Dashiel said to his sergeant that "It was nice knowing ya, Sarge" and then blissfully stating "It's about time I see what it's like from the other side." Dashiel then succumbs to his wounds and dies.