Side-kick

A sidekick is a slang expression for a close companion or colleague (not necessarily in fiction) who is, or generally regarded as, subordinate to the one he or she accompanies. Some well-known fictional sidekicks are Don Quixote's Sancho Panza, Sherlock Holmes' Doctor Watson, The Lone Ranger's Tonto, The Green Hornet's Kato, Shrek's Donkey (and sometimes Puss in Boots as well), Sonic's Tails (And occasionally Knuckles the Echidna as well) and Batman's Robin. (DC Comics)

The term originated in pickpocket slang of the late 19th and early 20th century. The "kick" was the front side pocket of a pair of trousers, and was known as the pocket safest from theft. Thus by analogy, a "side-kick" was a person's closest companion.

A humorous folk etymology refers to the sidekick's accomplishments being "kicked to the side" or otherwise ignored in favor of the more charismatic lead hero.

One of the earliest recorded sidekicks may be Enkidu, who adopted a sidekick role to Gilgamesh after they became allies in the Epic of Gilgamesh. Other early examples are Achilles and Patroclus in the Iliad, and Moses and Aaron in the Old Testament.

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