Complement proteins C5 and C5a are key drivers of the effector phase of the pathogenesis of pemphigoid diseases (PD), but the systemic inhibition of C5/C5a may be associated with severe infections. To generate site-specific therapeutics, antibody fragments against PD autoantigens will be fused with those against C5/C5a, resulting in classical bispecific antibodies and hemibodies which only assemble a second functional antibody domain after binding to their targets. The therapeutic potential of these novel reagents will be evaluated in vitro, ex vivo, and in different mouse models of PDs.