Safe to say, they both faced the consequences of their actions.
Or rather, all three of them, since Kael was caught up in the mess too.
Arthur wanted to resist and do some funny stuff; however, as it turned out, that buff demon was actually the mayor of the city.
Therefore, his strength was simply overwhelming, even for them to deal with.
Arthur might've been able to deal with it if he had some basic knowledge on how to fight.
After all, it was a bit stupid how the self-proclaimed smartest being in the universe didn't know how to fight.
But in the end, superficial knowledge was just that—superficial.
Nonetheless, they all found themselves in a certain jail cell, and despite Michael's best efforts, he couldn't be asked to get out and deal with the problems at hand.
Sure, the demon hadn't identified who was the one responsible for blasting the hole in the roof as well as the sky, but after not-so-careful consideration, it was determined that Kael was the one responsible.