During this time, Link also helps Midna find the Fused Shadows, fragments of a relic containing powerful dark magic. In return, she helps Link find Ordon Village's children while helping the monkeys of Faron, the Gorons of Eldin, and the Zoras of Lanayru. Once Link has restored the Light Spirits and Midna has all the Fused Shadows, they are ambushed by Zant. After he relieves Midna of the Fused Shadow fragments, she ridicules him for abusing his tribe's magic, but Zant reveals that his power comes from another source as he uses it to turn Link back into a wolf, and then leaves Midna in Hyrule to die from the world's light. Bringing a dying Midna to Zelda, Link learns he needs the Master Sword to return to human form. Zelda sacrifices herself to heal Midna with her power before vanishing mysteriously. Midna is moved by Zelda's sacrifice, and begins to care more about Link and the fate of the light world.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What weapon can transform Link back to his original self?
Master Sword