The Fiery Tolerance is both an item and a spell from the Witchery mod. This spell is a form of Imp Magic, and can be performed by a tamed Flame Imp. The Fiery Tolerance, when cast, will cause the victim to have long duration fire resistance. Using the contract on the Flame Imp will perform the spell. Combining this spell with a Taglock Kit of a creature in a crafting table will bind the spell to the creature, and will result in the spell being cast towards it. It will not work if the Flame Imp and the victim are in separate dimensions.
To be cast, the Flame Imp must have enough respect for its master, which can be gained by giving it valuable materials.