The Imprisoned

The Imprisoned is a character from The Legend of Zelda: Skyward Sword. It is a giant, mysterious beast who haunts Link's dreams. The Imprisoned dwells within the Sealed Grounds and Link will fight it on several occasions throughout his quest. The Imprisoned acts as the seal for Demise, one of the game's antagonists, and Ghirahim seeks to break this seal using the soul of Zelda.

Biography
After his failed attempt to obtain the Triforce, Demise was transformed into the Imprisoned by the goddess Hylia and trapped within the Sealed Grounds.

The Imprisoned eventually manages to break free of its seal, but Link manages to defeat it and restore the seal. Later, when Link obtains the Triforce, he and Fi use it to wish for Demise's destruction; in accordance with this wish, the Isle of the Goddess detaches from Skyloft and plummets back to the Surface, crushing the Imprisoned beneath it just as it was breaking free of its seal for a second time.

Unfortunately, Ghirahim circumvents this by kidnapping Zelda and traveling back in time to resurrect Demise in the past. Despite Link's best efforts to stop him, Ghirahim successfully completes the ritual; the Imprisoned emerges from its seal and devours Zelda's soul, allowing Demise to return.