"Fire resistance training is the first step you will need to be able to go on this expedition. Some of you lack the affinity for fire mana in general which means you may not have a high resistance to fire naturally. Others are weaker to fire mana in general because of your affinities." This was the same statement that su had made to several groups today.
These groups of soldiers had been prepared to go through the fire resistance training that had been set up over the coming weeks. This was to be sure that the soldiers, adventurers, and guards who came on this expedition would grow to be able to survive it much better than idf they did not have this training.
This was also so that those who could not improve enough could be weeded out and return to their other positions. Some people would not be able to gain enough fire resistance to be able to venture in to the fire elemental planes.