The initial plan of Immortal Knight's strategy was pretty simple. Zeroa fueled the altered elemental crystals with her mythical flames, overcharging them. She could trigger them with a burst of energy, which was exactly what she did.
The overcharged elemental crystals had been spread out evenly across the prophesied battlefield to cause maximum damage and destroy their enemies' formation. That worked out very well.
Following the successful attempts to stir chaos in the council's army, the well-hidden warriors revealed themselves and charged at the enemies from the front with the majority of the Trilance's power, and the flanks using the great prowess of their Elite forces and the reinforcement.