He won't pretend that he understands how a portal works or how a demon could travel through it but he intends to do much reading in the library so he is sure eventually he will have a better understanding of it. He still has much to figure out, having already been dealing with learning how a lot of the technology on the train works. There is so much that he has to come in contact with just in daily life.

"We travel around and help other places battle things they cannot handle themselves." It's really not that much different from night hunting or missions to other towns to help regular citizens against the spirits and other things that harass them on a day to day basis. Perhaps the enemies are different but the concept is the same and one he can easily latch onto in order to make all of this more acceptable.

"It is not surprising they have brought so many of us here."