Twilight Realm

Also see Twilight As Link regains consciousness and wanders out of the spring, he stumbles upon a strange portal -- a murky cloud of darkness leading to somewhere terrible. A hand juts out of the blackness and pulls him into the Twilight Realm. Sometime after leaving the Twilight Realm, Link goes after the Bokoblin king, dueling him for Colin's life. And that's about all the demo gives us. As for the events that follow immediately, very little has been said or shown about the Twilight Realm. The Twilight Realm is not the Dark World (from A Link to the Past). The Dark World was parallel to the light world (our dimension). In any given area both a Light and Dark world version existed, often different. The Twilight Realm is simply a darkness which absorbs the area it covers. That area is now a dead realm, and only the one dead version of it exists. This darkness is spreading from Hyrule outward and our adventure begins when it reaches peaceful Toaru Village and sucks Link in through one of its many portals. (Interestingly enough, this Twilight Realm seems to incorporate a fair amount of cel-shading -- a small throwback to the art style seen in Wind Waker, without the entirety of the cel shaded, cartoonish stylings, that so many people could never understand.)

As soon as Link enters this Twilight Realm, he is transformed into a wolf. This is apparently because, in the Twilight Realm, nothing from the normal world can exist in its standard state. As a wolf Link is feral, vicious, and brutal. He rampages through a terrible new world, destructive and terrifying, and is captured as a result. His actions in the Twilight Realm lead to him getting captured and chained up in some kind of castle.

While as the Wolf, Link is ridden by Midna an imp like character with great purpose, who at first saves Link and uses his new skills for her own doings, it is Midna who introduces Link to Zelda in Twilight Princess.