*We report a theoretical mechanism based on a 25 eV axion-like particle that simultaneously accounts for dark matter and dark energy. The model predicts a monochromatic emission line at 1.1 μm, within reach of JWST NIRSpec. This signature provides a direct, testable discriminant. No fine-tuning or anthropic assumptions are required. A detailed description of the underlying formalism and numerical pipelines is reserved for peer-reviewed publication.*