Many of us have had wargame units that have performed exceptionally compared to others in the same army. Sometimes better than usual and sometimes worse than usual.
Years ago when I got started with ancients using WRG IV, I fielded a Seleucid army. At first it included some 20mm Airfix Romans and some 20mm metal phalangites. IIRC the manufacturer was Brescia. At the time I was told that the Seleucids did not have Roman type infantry. Years later it was found that they did. One of the units in the army was a fifty figure formation of levy archers. The worst class of troops possible under the rules. They usually occupied a hill behind the main line of the army and would turn any unit that came in range into a pin cushion. Their morale never faltered. One time a friend and I played a Jewish revolt game. My friend took the Seleucids and I had the Jews. It may have been the first turn of the game or possibly the second, when the levy archers had to take a morale test. The result was an uncontrolled advance towards my army. They came in range of my archers, took some casualties, had to perform another morale test, and broke, fleeing off the field.
Some years later I ran an American Civil War campaign at the local hobby shop. It was a fictional campaign between the Empire (Union) and the Federation (Confederates). Star Wars had recently been in the theaters %). Commanders had names like J.B.T. Hutt or D. Vader. During one of the early battles a Confederate infantry brigade performed outstanding acts of valor, throwing back attacks by Union troops though greatly outnumbered. They became known as the St. John's Brigade due to their flag. Every time they were involved in a battle they continued to out perform all others. The Union players came to fear them and whenever there was a battle they would immediately try and locate the brigade. The St. John's brigade had started the campaign with 1500 men and over the course of the campaign they had eventually been reduced to less than 500 men. In their final battle the Union surrounded them with over three times their number and fired several volleys into them. There were few survivors. At this point the Empire had conquered most of the Federation and the campaign drew to a close.