21st Century Roman Legion in a military science fiction setting, blending classical Roman insignias with modern military aesthetics: Enlisted Ranks: Miles (Soldier): A simple bronze shield with a laurel wreath encircling a Roman numeral "I." Immunes (Specialist): A bronze shield with a crossed gladius and spear over the laurel wreath. Decanus (Squad Leader): A silver shield with a Roman numeral "X" and a red plume design at the top. Non-Commissioned Officers: Optio (Sergeant): A silver shield with a crossed gladius and shield emblem, surrounded by an oak leaf wreath. Signifer (Standard-Bearer): A gold shield with an eagle grasping a banner pole, encircled by a laurel wreath. Centurion (Senior NCO): A gold shield with a single vertical red stripe down the center and a bold Roman numeral "C." Junior Officers: Tesserarius (Lieutenant): A gold and red shield split diagonally with a stylized Roman numeral "L" and a lion’s head emblem. Tribunus (Captain): A polished silver shield with crossed gladius and an eagle in the center, overlaid by the Roman numeral "III." Senior Officers: Praefectus Castrorum (Major): A gold shield adorned with a fortress emblem, a crossed gladius and spear, and a wreath. Legatus (Colonel): A large, ornate shield with a golden eagle clutching a fasces, Roman numeral "V," and decorative laurels. High Command: Praetor (General): A round platinum shield with a sunburst design, a double-headed eagle, and Roman numeral "X." Consul (Commander-in-Chief): A rectangular platinum shield with a Roman fasces emblem, flanked by two golden eagles, encircled by a wreath with a crown at the top. These rank badges would be worn on the chest or shoulder armor, blending high-tech holographic projections with solid, traditional insignia for ceremonial and [...]