Nul-Spell

Nul-Spell is a status effect ability that makes a person immune to a specific type of damage, usually elemental.

Final Fantasy
NulBlaze, NulShock and NulFrost make their first appearance as White Magic spells in the original game, along with NulDeath and NulAll

Final Fantasy X
NulBlaze, NulShock and NulFrost appear as White Magic spells once again, along with NulTide. The four Nul-Spells are all located in Yuna's section of the Sphere Grid.