I'm not sure specifically as I haven't read it. But generally, a web novel with 'otherworldly hero business' might be about a hero's adventures in a different world, perhaps involving battles, quests, and character development.
Since I haven't had the chance to read 'circle zero's otherworldly hero business web novel', it's hard to say exactly. However, based on the title, it could involve a hero from a place called 'circle zero' who is engaged in some sort of business - which might be related to trading unique items or services in the otherworld. It may also include elements like meeting different races, exploring unknown lands, and facing various challenges to succeed in this otherworldly business.