Mephisto may have the power of fire, but Decapitron's electric laser ability is highly effective against dark sorcery. Plus, with the X-ray vision and high IQ, Decapitron can anticipate Mephisto's moves and counterattack with precision. In addition, the soul erasing crystal is a powerful tool that can render Mephisto powerless. Finally, Decapitron's machine guns can keep Mephisto at bay, and with the immortal ability, Decapitron can keep fighting until Mephisto is defeated. In short, Decapitron's skills are simply too much for Mephisto.