To deal with such a dangerous technique that cast illusions, the shadow lurker decided to sacrifice its body and trade blow for blow and that's why it ignored the blazing spear attack to launch an attack of his own. It refused to believe the blue scaled lizardman will be capable of withstanding more punishment after enduring Aldora's explosive attacks in the past.
Luckily for the beast, Kalos had plans of his own and chose to cover for the demon beast by placing a spatial gate where the attack. The duo was almost assured of dealing a critical blow to the lizardman, after which they will proceed to finish him off and then search for Francis and Diana to carry out their master's commands. But things don't always turn out the way we expect.
Puff!