On Co-creation of Daughter Universe by Black Hole and Universe with Derivation of de Sitter Universe Age, Dark Matter Source, Mass-sigma Relation and Decrease of Fundamental ‘Constants’ over Cosmic Time. ————————————————— Abstract: A model is given, linking our de Sitter universe, a black hole and their posited co- creation of a daughter universe (DU). Key relations for their masses and radii precisely parallel a core string theory entropy result. DU mass is a product of simple powers of the black hole and universe masses. The DU gravitation is posited to be a major source of the Dark Matter phenomenon, and also reproduces the Mass-sigma relation in galaxies. A universe age of ~13.82 billion years, and a ‘look-back-...