Silver Ragewing is the name given to the hero of the Pegasus legend of Nocturne.
According to legend, a powerful Shadow Dragon by the name of Nocturne, threatened to engulf all of Equestria in darkness for eternity. Just when the equestrians had lost hope, a shining silver Pegasus swooped from the skies and defeated the dragon with a flash of bright light, and Equestria was saved.
Little more is known about the mysterious Pegasus pony, but it is believed that after his battle he was knighted and retired to Cloudsdale, where some Pegasi still hold the Ragewing surname with great esteem.
A mural exists in the Silver wing of Canterlot, depicting the battle between the Pegasus and the ferocious dragon. The Silver Wing of Valor also owes its name to the legend of the Silver Pegasus.
It is also rumored that Silver held an Element-of-Harmony-like object which allowed him to defeat nocturne, but no record of such object has been found.