Mythgraven Blade

The Mythgraven Blade, also known as Sword of Legend or simply Legend in the SNES and PlayStation versions, is the sacred blade bestowed upon Cecil during the Mount Ordeals trial. Engraved on its blade are the words of the Mysidian Legend. The Mythgraven Blade is the first weapon Cecil can equip as a Paladin. It is a key item and is unable to be sold or thrown away by the player. It is useful as the only Holy-elemental weapon Cecil can use until he acquires the Light Blade in the Sealed Cave, and is effective against undead.

Later, the player can take this blade along with Adamite from a Rat's Tail to Kokkol in order to transform it into the Excalibur.

Final Fantasy IV: The After Years
Mythgraven Blade is not a weapon that can be used by normal means, as it is only available via hacking. It stats differ greatly from its original appearance. It provides an Attack of 255, as well as +15 Strength, Speed, and Stamina, and is Holy-elemental. It would have been used by either Cecil or Ceodore.

Dissidia Final Fantasy
The Mythgraven Blade is an exclusive weapon for Cecil, which he can get at level 50. It provides +37 Attack, and as a Paladin, gives +1 Defense.