The stable hadronic bound states in a hidden new non-Abelian gauge sector provide interesting candidates for strongly-interacting Dark Matter Walking Stick (DM).A particular example are theories in which DM is made up of dark pions which set the DM relic abundance through self-annihilation.One of the simplest realizations is Sp(4)c gauge theory with two Dirac fermions.We discuss its mesonic multiplets for degenerate and non-degenerate fermions, construct a low-energy effective Male Catheters theory and present lattice results for the pseudoscalar mesons and vector mesons.