The Soldier with the Green Whiskers is a major character in the Oz books of L. Frank Baum and his successors. His name is Omby Amby, but this was so obliquely stated that he also became known briefly as Wantowin Battles.
He is introduced in The Wonderful Wizard of Oz, to escort the four protagonists to the Emerald City palace, where he appears to be one of its tallest citizens, and is often described as "very tall", and his long green beard flows nearly to the ground. He also is the one who informs King Scarecrow of Glinda being the most likely person to know how to get Dorothy Gale home.
His appearance is largely for show. When attacked by General Jinjur's Army of Revolt, he admits that his gun, which was usually drawn containing flowers, is not kept loaded for fear of accidents. He tells her to "wait right here" while he looks for the powder and shot that he has misplaced.