SPOILERS
Max doesn’t seem to have an ember in the first place. There’s even this line during the last battle in his route:
“Without using Arts or an Ember, Max empowers his allies by acting as the observer, the strategist, the commander, and the encourager all at once, just by the power of his expression.”
Primal Palm seems more like a physical technique than an ember. What Max really does is use music to encourage and support his allies.