considering the mc basically kidnapped the holy sword and spends his free time trying to molest her, evil is pretty much a relative concept.
though my money is on the guy being relatively benign, but the bullshitter family obstructs their intentions to clear up the muddled history of the hero and/or will try to exploit the holy sword since she's the real deal.
The way I see it going is that MC isn't really one to hold her back and lets her stay. But it turns out the guy is like super boring/annoying and when compared to MC's galavanting about in search of imperials is much more like a hero she slowly and begrudgingly rejoins the party.