There were a lot of things happening in the battlefield all at once. Aside from the fact that Aeolus and the two commanders were about to end each other's lives, the [Particle Cannon] was also nearing its full charge. In fact, it would probably take a few seconds after the fight of the generals in order for it to fire.
Selena would've poured all her remaining mana including her life force into the barrier just so it could defend against the said attack but, something unfortunate happened. A figure came down from the skies, with gigantic wings that resembled that of a raven's.
As soon as he landed on the ground every spell being casted was nullified immediately. This included the waters of Aeros and the skills of the generals.