Bill Foster is a biochemist and a former member of SHIELD who had previously worked with Hank Pym on Project GOLIATH until disagreements between them caused Pym to dismantle the project. During one of the SHIELD missions he met Ava Starr girl whose exposure to the Quantum Realm made damage to her body. When SHIELD collapsed he tried help Ava cure her with all research that Pym was doing to bring Janet van Dyne back from the Quantum Realm. he helped Ava until Janet was rescued and then cured her.