A little too rushed. Sounds like the author has a lot of ideas in his head and tries to skip the 'boring bits' in his head, but explanation for such a serious isekai should be shown. I hope it gets elaborated further.
@ everyone complaining about his coatume choice:
it will let him become invisible when he sits down on a bench! or stands in the middle of a bunch of monks! seriously, it worked for Altaiir!