A few moments before Basil confronted Charles—just as he arrived at Raneil Barony, Iliana and the other Legion Commanders who had combined forces with the Legions under Edward's lead arrived at BA-32.
Edward was the one who had concocted the counterattack strategy, so everyone let him, rightfully, lead the army.
Iliana and the six Legion Commanders who had been stationed in Woster County actually led and brought more people than Edward with them, but none of them was willing to lead the army even though they had the qualification to.
All of them, knowing that Basil would come join them soon (according to Edward), were reluctant to command the army because they didn't want to mess the situation up.
They preferred letting Edward lead the army according to his strategy rather than leading their soldiers independently and risked causing trouble for Basil when he took over.