Ragnarok (summon)

Ragnarok (ラグナロック Ragunarokku) is a recurring summon in the series. It usually takes on the appearance of a sword.

Final Fantasy VI
Ragnarok is an Esper, not to be confused with the sword, even though the Magicite can be used to make the sword. It is obtained in the Weapon Shop in Narshe in the World of Ruin. Locke is needed to access the shop. The owner in the back offers to hand over the Magicite or refine it into the sword. If the player chooses the Magicite, its summon, Metamorphose (Metamorph in the original version), transforms an enemy into a random item. Its Hit Rate is dependent upon the target, and it is not affected by the Vanish-Doom Bug. It costs 6 MP to summon, and it teaches Ultima at a rate of X1.

Since Ragnarok is the only esper to teach Ultima, many players take the esper instead of sword, thinking they'd miss out on Ultima otherwise. However, if one has enough patience to remove the curse from the Cursed Shield, they'd receive the Paladin Shield, which can teach Ultima at the same rate. This allows players to take the sword instead of the esper, which they can then trade at the Dragon's Neck Coliseum for the Lightbringer, the game's strongest weapon.

Final Fantasy Fables: Chocobo Tales
Ragnarok is one of the five Promo cards. In the Japanese and American versions, he must be downloaded from a download station. In the European version, the player simply has to enter the code A, L, Left, Up, R, R on the Download Pop-Up Card screen.

Final Fantasy XIII
Ragnarok appears in Final Fantasy XIII as an Eidolon, but cannot be summoned by the player. It instead plays a major role in the main story.