Kurikara

The Kurikara is a weapon that has been made indestructible by Isshin. It was first used by the Scarred Union Hunter before it was stolen by Andy made into his signature weapon.

Overview
Kurikara is a katana with gold highlights and a black hilt. It is engraved with the kanji for "Unbreakable" at the cap of it's hilt.

History
It was created by Isshin at some point in the past and given to Scarred Union hunter. After said hunter was defeated by Andy and Fuuko in Chapter 1, Andy took it for himself and has continued to use it since.