A mecha design of a justice-seeking combat robot, featuring a heavy full-armor chassis with boxy angular frames and exposed cables, caterpillar tracks as legs, a cylindrical head sensor that glows as it locks onto a target, wielding a beam-edged chainsaw weapon that sprays sparks when slashing, equipped with an anti-missile catapult and a thick shield, soaring over a swirling sandstone desert under a dramatic overcast sky. Dust and oil stains are visible on its scarred armor, with a cinematic dynamic angle, intense amber sunset lighting casting long shadows, gritty realism and kinetic energy, volumetric sandstorm particles mixing with sparks and smoke. Rusted, decayed, and half-sunken remains of a giant soldier.