After he finished setting up his illusion, Angor immediately sat on the ground and panted badly. His clothes were drenched in sweat.
"I… it was so tiring, to deploy an illusion inside Nightmare Domain…" He almost exhausted his mana reserve to create a low-level illusion which was mostly thick mist.
Then, he looked at Shadow, who was wandering aimlessly in the illusion. At least it looked successful.
The tactic was described by Sunders in The Mystery of Nightmare Domain. According to Sunders, he could turn everything to his advantage by deploying illusions right inside his Nightmare Domain, and since such illusions did not have breakable nodes, it meant anyone trapped in them would find it extremely hard to escape.