Background: The Unified Theory of Multiversal Genesis (UTMG) proposes a novel cosmological paradigm where the universe emerges from the quantum vacuum through fluctuations of a unified field Φ. This process leads to the formationof multiple universes that interact via mechanisms mediated by strings and fields, resulting in a complex and interconnected multiverse.Methods: We developed a theoretical framework that unifies concepts from quantum mechanics, general relativity, and string theory. Detailed mathematical formulations describe the origin, evolution, and interaction of universes within amultidimensional bulk, employing advanced field equations and brane dynamics. Numerical simulations analyze the phenomena predicted by the theory, with justifications for the approximations used.Results: The UTMG provides equations governing the nucleation of branes from the quantum vacuum, iterative processes of universe multiplication through spontaneous symmetry breaking, and mechanisms of inter-universal interaction mediatedby open strings and the unified field Φ. The simulations support the theoreticalpredictions, showing brane formation and gravitational wave generation, with implications for observable signatures. Conclusions: The UTMG offers a coherent description of the genesis of themultiverse and inter-universal interactions, providing potential explanations to unresolved problems in cosmology. The theory’s predictions could be tested with future experiments and observations, opening new avenues for exploration in fundamental physics.