I'm pretty sure no one mentioning Islam in that chapter. Its a fictional story, with a bit of reference from culture and real world religion. The church in this comic is also never mentioned whether its a christian church or whatever. its just church. same with this character. He's just some royalty from neighbor kingdom with different culture that was inspired from real world. And the character with the said religion is not very nice people. So what, just enjoy the story. People also behave like that in the real world, some of them nice, the other's is not. Even if the brown religious envoy is not nice, its also looks like some opportunity to develop his character. He's to handsome looking to be some one time character. The crown prince is also not so likable at first, but he's gradually developed.