Eminent Student Of Buddha
Ehm droppin a late opinion here. He is literally going to places worse than that tavern to make deals and search for thing. Also accounting to the fact that more people with see her if she goes around the city with him. If he brought his sister and with her charm, it would just bring endless trouble and I think would be more dangerous than leaving her in the tavern. Also the witch, he doesn't really know her. For all he knows shes a perverted b*** thats gonna kidnap his sister. So personally I don't think it's really forced. You just have to be open to the fact that different people, different views hehe.
well looking past that he left her there. it was a good first blood. only way a loli that has only talent but no training nor experience. fighting dirt works well. also every single thing that she did has been foretold. (meaning she didn't suddenly drag out a new spell or weapon (something MC does in quite a few novels :P))