Unlike the Greeks who pretty much used them as a way to make their warriors look taller and more imposing, the plumes of the Romans were designed for practicality as is essential in a standing professional army. In terms of raw strength, the Roman would have it.

What is the purpose of a plume on a helmet?

Throughout history plumes have served a number of purposes in military culture. Worn on helmets that all but obscured a soldier’s face, they indicated his allegiance. Some plumes distinguished military commanders, and some were used as regalia for special military units.

What is the red thing on a Roman helmet?

Some of the helmets used by legionaries had a crest holder. The crests were usually made of plumes or horse hair. While the fur is usually red, the crests possibly occurred in other colors, like yellow, purple and black, and possibly in combinations of these colors such as alternating yellow and black.