Mowgli...
Mowgli is the most recognizable character fromThe Jungle Book, thanks in part to all the movie and stage adaptations that cast him as the star, but also because he's the protagonist in three of the book's stories.
You might think you might know Mowgli if you've seen him elsewhere, but book Mowgli is quite a bit different from Disney Mowgli. He's usually butt-naked, for one thing. And being raised in the jungle isn't all sing-alongs and playing with cuddly bears—Mowgli can be violent and kind of scary. This is the result of being taught the rules of the jungle.
Mowgli is a fish out of water from the beginning. Or should we say frog out of water? Mowgli means "little frog" (1.44), after all, likely a reference to his wriggly nature and his lack of a thick coat of body hair, unlike the wolves that raise him.
The jungle isn't a nice place. It's a place where animals have to kill to survive. So, in order to survive, Mowgli, too, has to hunt and kill, and keep himself from being hunted. Shere Khan, the tiger, hunts Mowgli from the get-go, but Mother Wolf says that one day Mowgli will grow strong enough to kill Shere Khan instead.
And you know what? She's right.
Jungle Boogie
The first two stories starring Mowgli show him being raised by the Wolves and his mentors, Bagheera and Baloo. Together, they teach him to survive, and Baloo makes him learn all the "Master-Words" (3.10) so that he can communicate to any creature in the jungle.
And what does this get Mowgli? It gets him expelled from the Wolf Pack.
See, most of the wolves aren't that bright, and they let themselves be manipulated by Shere Khan into voting Mowgli off the island—err, out of the jungle. So Mowgli goes to live with other humans. He cries when he leaves the jungle: "I do not know what this is. Am I dying, Bagheera?" (1.139), he weeps. Animals, like big boys and baseball players, don't cry, so this show of human emotion is strange for Mowgli.
Mowgli is an outsider in the world of man, too, though—the kid just can't catch a break. He has to learn the rules of man and their language, because the villagers think he is "as silly and dumb" with them "as a man would be […] in the Jungle" (5.12). Of course, they mean dumb as in silent, not stupid; Mowgli is far from stupid. The villagers on the other hand are just as bright as the wolves (i.e. not very), so they kick Mowgli out as well after he kills Shere Khan and defies the village's top hunter.
After being rejected by both his tribes, Mowgli ventures into the jungle basically by himself, and must survive as a true lone wolf.