text: A sidekick is a slang expression for a close companion or colleague who is, or is generally regarded as, subordinate to those whom they accompany.
  Origins
  The first recorded use of the term dates from 1896. It is believed to have originated in pickpocket slang of the late 19th century. The "kick" was the front pocket of a pair of trousers, believed to be the pocket safest from theft. Thus, by analogy, a "side-kick" was a person's closest companion.
  One of the earliest recorded examples of a sidekick may be Enkidu, who played 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.