The Fire of Fate is the name of the Great Seer Mhata's ability to foresee the future; and it is one of its abilities that made her stand out among all the elemental lords.
Although her main offensive abilities are still based on the fire elemental authority that she wields, against a Dragon with access to Fire Elemental Authority while having the Ancestral Dragon's essence and a body that has gone through multiple tempering, is not something her own fire can deal with anymore.
What really made her confident in all her dealings is the future guidance that she could conceive. However there was a major drawback, and that is the mere fact that she could predict them, which also means the future could be modified.
All these times, she made sure that every action of them are aligned to the perfect timing of fate's track so as to keep the future that she wanted. However, she is not in complete control.