Kooritsurugi

The Kooritsurugi is a ancient sword owned by the Kirihara Family.

Features
It resembles a katana, however, its blade is ice blue and shares a color of ice and blue.

Description
This sword can be only used by Shouichi, Seijiro or Haruto. It's used during battles, and it freezes the enemy and kills them. Taiga can also use it as he is the reincarnation of Haruto.

"Chapter 2: The Cursed Past"
It is mentioned when Taiga has a memory of Haruto battling Shouichi Kirihara.

"Chapter 3: Yukiko"
Taiga and Kayako try to retrieve the sword, but Kayako gets thrown by force. She enters the room again, and sees Taiga holding the Kooritsurugi in hand.

"Chapter 4: The Tale Of Yukiko and Haruto"
It will appear in this chapter.

"Final Chapter: Frozen Fate"
It will appear in this chapter.