Neutrino masses are the least understood sector of the Standard Model. Their absolute values are unknown, only squared differences have been measured, and whether neutrinos are their own antiparticle (Majorana) or distinct from antineutrinos (Dirac) remains experimentally open. This paper derives all seven neutrino sector parameters from the Pentagon Physics framework. The three masses (normal ordering: m₁ = 10.06, m₂ = 13.29, m₃ = 51.30 meV, Σm = 74.65 meV) follow from the axiom. The four PMNS mixing angles are derived from character table structure. Majorana character is proved: all 81 characters of 2I are real, so no complex representations exist, excluding Dirac neutrinos.