Blade of Tathagata looks like an ordinary katana with grey hilt, yellow pummel, and a black sheath.
Despite its rather ordinary appearance, the blade has a tremendous cutting power. A single slash can easily cut an entire island and cut Hui Mo-Ri's Ruyi Jingu Bang. Later when The King regained his youth, a single slash completely broke a clone of Ruyi Jingu. another example is that the katana, in its steath, manage to cut Sang Man-Duk's summoned sword. The Blade itself can be summoned, but it appears to consume energy, since The King in his old body can't summon when it was knocked out of his hand. the blade can also be regenerated when its broken.
The blade of Tathagata exhibited fire-related ability, as it was seen engulfed in flame when The King was enraged.
like all national treasure, it can only be wielded by those who it recognize as its true owner. In this case, the blade only recognize those who comes from Okhwang's lineage or his Physical Power (The King's Body).
- It is unknown if The King is the true owner of this sword or if it is given to him by Tathagata.