"Heavenly Gatekeepers" 

The stone would be destroyed within seconds and this means the domain would start crumbling. 

Of course, Ainsley chose to use a fake stone instead of a real one because she was afraid that Gabriel would be able to grab the stone before it entered the gate and then return with it. 

If that happened, not only the plan to kill Gabriel would fail, but Ainsley would never be able to destroy the domain core anymore. 

Because of this, Ainsley wanted to use realism art to push her luck and try to fool Gabriel because the realism art had the breath of the light camp and the item or living beings created out of this ability would also have the breath of the light camp. 

This was a disadvantage when drawing dark camp-related items or creatures, but people in this world didn't really care about the two camps. 

Of course, if Ainsley wanted to fool the demons instead, it would be hard, but she used this ability against the angels...