Every aspiring Firebelly must enter the caldera of the titanic volcano, Fire Mouth, where the heat is such that their hair is burnt from their bodies. There they must fill a crucible with roiling lava and down it in a single draught. Only those with the blessing of the volcano god can survive.
A model with this special rule has a 4+ Ward save against any wounds suffered that were caused by an attack that has the Flaming Attacks special rule.