Horst Eisele was a German man who served as an undercover agent for Baron Strucker's faction of HYDRA. He traveled to the US where he was recruited by Donald Birch to work under the shadows within S.H.I.E.L.D. under the name "Charlie Russo". When Captain America exposed HYDRA to S.H.I.E.L.D., Horst was given orders by his superiors to launch Project Insight, but failed in the resulting battle. While thought to have perished, he and group of surviving HYDRA personnel survived and escaped onboard one of the last Quinjets that remained standing on one of the three Helicarriers.