The author established a screening process from a mirror-image VHH (d-VHH) library using chemically synthetic mirror-image proteins (d-proteins) and phage display technology. Additionally, the author synthesized the hepatitis B virus (HBV) full-length core protein [Cp183(C183A)] and interleukin-6 (IL-6). Overall, this work paves the way for exploring novel protein therapeutics from unexplored mirror-image biomolecules.