Shere Khan is a fictional Bengal tiger and the main antagonist of Rudyard Kipling's "Jungle Book" and its adaptations. According to The Kipling Society, the word shere (or shir) translates as 'tiger', and khan is a title of distinction, used together "to show that he is the chief among tigers.

Shere Khan is depicted by Kipling with being born with a crippled leg and was derisively nicknamed "Lungri" ("The Lame One") by his mother. Despite this condition, Shere Khan is arrogant and regards himself as the "rightful" lord of the jungle. The only creature who looks up to him is Tabaqui, a cowardly and despised golden jackal.

In "Mowgli's Brothers", Shere Khan's failed attempt to hunt humans causes a human "cub" to stray from its parents. When Shere Khan discovers the infant, it has been adopted by Indian wolves, Raksha and Father Wolf, who have named the child Mowgli. Mowgli is accepted into Akela's wolf pack and is protected by Bagheera (a panther) and Baloo (a bear). Furious at losing his kill, the tiger swears that the boy will be his some day.

More Info: en.wikipedia.org