This was the first time Adam had ever seen sound-wave magic.
Fear Roar was the name of Peter's spell: it used spiritual power to vibrate the ether and emit ultrasound, and killing was its whole purpose.
Ultrasound's piercing power and tight focus, combined with the magical force of Soul Rend, finally shattered Adam's electromagnetic barrier and struck his body. But in the very instant Peter Om's joy peaked, Adam vanished from where he stood.
Ancient mages had no elemental true body.
Their souls ascended differently from those of mainstream mages—not a complete transformation, merely a reinforcement of what was already there. A soul without the protection of Mage Armor could not withstand the buildup of high-grade energy. In other words, Peter Om's flesh was his greatest weakness.