Kusanagi

The Kusanagi is a Light Blade that is found in the Debug Menu of the original Golden Sun. It is an Artifact that increases base Attack by 135. This weapon is impossible to access during normal play and can only be seen using a hacking device. It does not have an Unleash effect coded for it. This weapon's graphic is officially used in Golden Sun: The Lost Age for the Light Blade artifact Masamune. If it had been in the original game, it would have been the most powerful Light Blade, surpassing even the Kikuichimonji (assuming it would have had a proportionally strong Unleash effect coded as well).

If this weapon is in the party in a Clear Data file and the file is transferred into The Lost Age, it will be replaced with the Masamune.

The Cloud Brand, an acquirable weapon in The Lost Age, is known as the Amakumo no Tsurugi in the Japanese version, which is another name for the Kusanagi no Tsurugi of legend. Curiously, the Kusanagi looks nothing like the Cloud Brand, and is a Light Blade, as opposed to the latter being a Long Sword.

Cultural References
The Kusanagi no Tsurugi is a legendary Japanese sword as important to Japan's history as Excalibur is to Britain's, and is one of three Imperial Regalia of Japan. In Japanese legend, it was found by the Storm God, Susanooh, in the tail of the Orochi dragon, after he killed the beast for terrorizing the land of Izumo and married the sacrificial maiden, Kushinada. Later, Susanooh gave it as a reconciliation gift to his sister, the Sun Goddess Amaterasu, who bequeathed it to Prince Ousu, also known as the Yamato Takeru, the progenitor of the Japanese royal family. Kusanagi's high profile has made it popular, appearing in various works of fiction. It is rare for characters to actually use one in a combat, as it is a ceremonial weapon. Instead, its magical properties are stressed. It is sometimes misrepresented as a katana, because it is a Japanese weapon. Kusanagi is allegedly kept at Atsuta Shrine to this day, although it is not available for public display, and its existence cannot be confirmed.