The audacity to come into someone else’s house and bully a girl who's a few years his junior. Not to mention, it's his blood-related little cousin. How atrocious can one spoiled brat be?
Granted, he’s the heir of the Ichihara Construction but does he think he owns them because they’re within this compound? What a load of bullshit.
This is just Ichihara Jun being an asshole to everyone because he has never been reprimanded by his daddy dear. He can always get away with it because someone will keep wiping his ass for him.
The future of their company is grim if he ends up inheriting it. Either he's going to be a tyrant and flunk their reputation or he'll be surrounded by bootlickers who will do his work for him in exchange for benefits.