The moment Annan shattered the Wall of Ash with the Brilliant Sword.
The holy domain filled with the [Understanding] Element automatically functioned, analyzing the numerous buff spells previously cast on himself by the Gray Professor; and with the [Strict] Element, they all disintegrated...
After that, Annan immediately started to feign charging up. The Gray Professor, lacking adaptive capabilities for the Radiant Element, couldn't perceive through that quality of light to see what Annan was doing inside.
It was even less likely for him to realize that Annan was actually grasping [Vatore's Rite] in his left hand, silently activating it.
—— At the same time, the Gray Professor mistakenly assumed that Annan's Elemental Power could directly reduce the energy of the Wall of Ash, so he would surely defend fully on the spot.