Rozan used [Multi-Casting] that allowed him to cast various magic at the same time. He protected everyone and always cast magic that was strong against the magic that Astaroth used.
So far, he had managed to piss Astaroth off, and based on the information they got after fighting Astaroth, [Foul-Breath of Death] couldn't be used over and over. They used that information and tried to wear him off because, for some reason, Astaroth couldn't be killed with anything.
"Is he immortal?" Jeanne asked Aurea.
"If he is, then he shouldn't feel inferior to the other Demon Kings. There must be a reason why he can survive even after getting mutilated over and over," Aurea answered and observed Astaroth for his weaknesses since she also didn't know. "I mean, we are here as a backup plan if they can't kill him. So, let's just stay here and hope that we don't have to butt in," Aurea continued.
Jeanne hummed in agreement and thought about what kind of power Astaroth hid under his sleeve.