Scimitar of Twilight

The Shadow Scimitar is a sword made and used by Zant to resurrect Stallord in.

Location and Uses
When Zant confronts Link in Arbiter's Grounds, he stabs the sword into the skull of the fallen beast Stallord, awakening the once dead creature, and beginning the fourth boss battle. It is unclear if the Shadow Scimitar has any other powers, as it is not used or seen for the remainder of the game. It is possible that it gave Stallord many of the powers he has such as calling upon Staltroops and flying after losing his body. The sword, because it is impaled into the head of Stallord, contributes to the heavy amount of damage that it takes during its Critical Point in the second half of the battle, after destroying his spine.

Hyrule Warriors
The Shadow Scimitar appears in as a weapon used by Zant.

Trivia

 * Though it is known as a scimitar, it does not actually resemble a real scimitar.