We introduce the Unfolding Equation as a universal dynamical law that governs discrete complexity growth in any system that exhibits branching or proliferative structure. The equation is Jn=10λn(2ω(n)−2) J_n = 10^{\lambda_n} (2^{\omega(n)} - 2) Jn=10λn(2ω(n)−2), where Jn J_n Jn measures complexity at step n n n, λn \lambda_n λn is a baseline structural exponent, and ω(n) \omega(n) ω(n) is the effective branching function. Unregulated, the equation produces sub-exponential, exponential, or super-exponential regimes depending on ω(n) \omega(n) ω(n). Regulation is achieved through exponential damping at the resonant-critical parameter θ\eff≈0.237085 \theta_{\eff} \approx 0.237085 θ\eff≈0.237085, which emerges as the unique internal fixed point of the coupled system. This value is not externally tuned but is derived from the requirement that the unfolding, when coupled across sectors via Wide Net matrices and reduced via iterative seesaw operations (Schur complements), simultaneously suppresses divergence while preserving cross-sector information. The resulting contraction κ=1−θ\eff2≈0.944 \kappa = 1 - \theta_{\eff}^2 \approx 0.944 κ=1−θ\eff2≈0.944 enforces bounded observability wherever the system admits unification. We demonstrate the framework’s universality through applications to analytic number theory (damped explicit formulae), Diophantine equations (Beal Conjecture), and categorical geometry (Geometric Langlands). Numerical simulations and asymptotic analysis confirm that low-mismatch regimes stabilize at bounded attractors, and high-mismatch regimes diverge super-exponentially. This provides a dynamical explanation for stability and instability across domains. Complete appendices provide derivations, code, tables, and operator bounds.