550th Solar Legion

The 550th Solar Legion is an elite Clone trooper unit. The history of the 550th dates back to the days of Red Solaris in Twoearle's homeworld, when the legion fought under her command during the First Ultimeguil War. The men of the 550th had an unwavering loyalty towards Red Solaris, even volunteering to stay under her command when she attempted to stage a coup against the ruling United Republic, where they were badly defeated.

The Clone troopers of the 550th during the First Ultimeguil War wore Phase I armor painted in dark red, but during the Second Ultimeguil War, the legion wore Phase II armor and changed their colors to blue.

After the end of the Second Ultimeguil War and the Twin-Tail Purge, during the rise and expansion era of the Solar Empire, the 550th Legion has grown to become the single-largest legion in the Imperial military, having recruited many other Clone troopers from numerically-reduced units and regiments as a result of large casualties and attrition. During the Imperial era, Tailred has deployed the 550th on campaigns mainly to subdue remnants of Twintail forces and to quell numerous rebellions within Imperial territories, which gained the legion a fearsome reputation as the Empire's most brutal enforcers. The legion was placed under the command of an armored knight that came to be known as the Silver Legionnaire (formerly ARC-0555 "Fives").