Yata Mirror

The second of Itachi Uchiha's weapons which he added to his Susanoo, the Yata Mirror provides one of the highest defenses ever seen in the series, increasing the Susanoo's already formidable defenses to a higher level. The Yata Mirror is a one of the three legendary treasures, and being endowed with all nature transformations, it can change its own characteristics depending on the characteristics of the attack it receives all changes its chakra nature to block nearly all attacks. Zetsu claimed that, this, combined with the Sword of Totsuka, essentially made Itachi invincible. Only Kirin has shown the firepower required to overpower the Yata Mirror's defense; even then, it managed to save Itachi from death.