Shuichi Shirato is basically the class snob—rich, uptight, and never lets anyone forget it. His family owns one of the best restaurants in Doumori, so naturally he spends half his time taking shots at Nube's taste in food and general lack of fancy possessions. Nube finds him insufferable most of the time, but here's the thing: whenever Shuichi actually gets tangled up with a youkai, his teacher shows up to help him out anyway.
What's interesting about Shuichi is that he's kind of skeptical about the whole youkai thing. Instead, he's way more interested in aliens and cryptozoology—basically anything that proves there's more to the supernatural than just Japanese folklore. He keeps trying to push this angle, only to have Nube end up saving him from a youkai anyway. It's a running dynamic between them.
Despite being kind of a jerk on the surface, Shuichi isn't actually a bad person. He genuinely loves animals, and he's proven it too—he once went so far as to be willing to sacrifice his own life to stop an angry youkai that had originally been a puppy. That kind of commitment says something about his actual character underneath all the arrogance.
Content compiled by AnimeList.moe from publicly available sources.