  We continue our study of the semi-classical (large central charge) expansion
of the toroidal one-point conformal block in the context of the 2d/4d
correspondence. We demonstrate that the Seiberg-Witten curve and
(epsilon1-deformed) differential emerge naturally in conformal field theory
when computing the block via null vector decoupling equations. This framework
permits us to derive epsilon1-deformations of the conventional relations
governing the prepotential. These enable us to complete the proof of the
quasi-modularity of the coefficients of the conformal block in an expansion
around large exchanged conformal dimension. We furthermore derive these
relations from the semi-classics of exact conformal field theory quantities,
such as braiding matrices and the S-move kernel. In the course of our study, we
present a new proof of Matone's relation for N=2* theory.
