Tsujigiri Itachi

The Killer Weasel (辻斬りイタチ) is a creature developed by Dr. Indigo for Shiki's plot to use monstrous animals to attack East Blue to force the World Government to submit to him.

The gale's Reaper, using only one hand he comes striking down with his handmade scythe. He carries his agile body exactly as if it was a gale.

Trivia

 * The Killer Weasel's original name is 辻斬りイタチ/つじぎりイタチ/Tsujiri Itachi. The word tsujiri literally means crossroad killing, which refers to the practice in the Edo period of Japan in which bushi (samurai) would kill a random bystander in order to test out a new sword.  It would later refer to other needless killings committed by the bushi, and was considered socially acceptable for a time.
 * The theme of the Killer weasel comes from the Japanese folklore monster known as the 鎌鼬/かまいたち/kama-itachi, or sickle weasel. It would travel through fierce winds and give people gashes with is sickle shaped claws.