Continues the analysis of light-fermion effects on a magnetic monopole’s charge degree of freedom, showing the Fermi vacuum near the monopole core is strongly perturbed despite weak gauge coupling — completes the Callan-Rubakov derivation with Callan’s “Disappearing dyons” and Rubakov 1981. relevance_note: second half of the Callan derivation establishing the monopole-catalysis cross-section scale, the number that determines how dangerous a produced monopole would actually be.