A dynamical mechanism, based on a confining non-abelian dark symmetry, which generates Majorana masses for sterile fermions, is proposed. We apply it to the inverse seesaw scenario, which allows us to generate light neutrino masses from the interplay of TeV-scale Pseudo-Dirac mass terms and a small explicit breaking of lepton number. A single generation of vector-like dark quarks, transforming under a  SU(3) gauge symmetry, is coupled to a real singlet scalar, which serves as a portal between the dark quark condensate and three generations of heavy sterile neutrinos. In this framework the lightest dark baryon, which has spin  3/2 and is stabilized at the renormalizable level by an accidental dark baryon number symmetry, can account for the observed relic density via thermal freeze-out from annihilations into the lightest dark mesons.This model may be probed by next generation neutrino telescopes via neutrino lines produced from dark matter annihilations.