A biochemist who is frightened of everything alien and superhuman, on a team that deals with nothing else.
Jemma Anne Simmons joins Coulson’s team as a specialist in both human and alien life sciences, and is close to Agent Fitz from their time at the S.H.I.E.L.D. academy. She grows to mistrust everything alien and superhuman, and proves her loyalty to Coulson anyway when the rival S.H.I.E.L.D. faction arrives. Elizabeth Henstridge plays her.
The mistrust is the interesting part and the series keeps it. She is not squeamish, she is a scientist who has read the containment reports, and the show makes her argue her way out of it rather than simply grow out of it.