Lumian broke the monsters in the dream ruins into three levels based on how the flaming monster and the three-faced monster reacted when they encountered him.
The lowest level ones acted on instinct alone. As soon as they saw him, they would attack. When he activated or partially activated the black thorn symbol on his chest, they would immediately give up and submit fully to his mercy.
The higher level ones would hunt him down before he partially activated the black thorn symbol. After he finished the sacrificial dance, they would cunningly opt to escape. But they couldn't sense the existence of the black thorn symbol beyond five meters. The flaming monster likely only remained in fear and associated the corrupting aura from the seal with Lumian.