Kagejitsu! Episode 15 \/\/FREE\\\\
In the Kage-jitsu episodes, it is shown that Delta can generate a strong air shock wave, just by exerting force from his arm without hitting someone directly, although the wave as such is not harmful to one, it is speculated that it is It would take a lot of raw force just to generate such a wave. This is seen when Delta accidentally breaks the magic absorption nullification artifact, made by Eta which she shows to Alpha.
Kagejitsu! Episode 15