Unlike what everyone present thought as they watched the battle and heard Asmodeus' furious roars, the Demon King wasn't actually consumed by anger.
Instead, he was excited. Like most Demon Kings, Asmodeus harbored a burning desire deep within his heart. And by fighting a powerful opponent, that desire only grew stronger.
At first, he had merely intended to kill Clyde quickly, to teach a lesson to the human who had dared to reject his offer long ago—and now even had the audacity to steal his artifact. But instead, he found himself in a battle that filled his chest with exhilaration.
The fact that Clyde wielded Angelic power only fueled Asmodeus' enthusiasm, like pouring oil onto an already blazing fire.
There were almost no opportunities for him to fight an Angel—their natural nemesis—because of the ceasefire agreement established after countless devastating wars.