Doctor William Barrett "Bill" Foster is a biochemist and a former member of S.H.I.E.L.D. who had previously worked with Hank Pym on Project G.O.L.I.A.T.H., also giving hime the codename Goliath, until disagreements between them caused Pym to dismantle the project. During one of the S.H.I.E.L.D. missions, Foster met Ava Starr, a young girl whose exposure with the Quantum Realm caused severe damage to her body. Once S.H.I.E.L.D. had collapsed, Foster helped Starr cure her condition, using all research that Pym was doing to bring Janet van Dyne back from the Quantum Realm, while both Ant-Man and the Wasp stood in their way. Although he disagreed with her methods, Foster continued helping Starr until van Dyne was rescued and then cured her, as Foster agreed to protect Starr as they went on the run.