So grandpa is a grand shit, huh? For real, that piece of shit thinks he can get away with being a piece of shit and to a degree he can, but you shouldn't truly anger the people you live with. If she had wanted vengeance, she could have assassinated her grandfather before leaving. Maybe here it's more difficult, but really, don't anger the people you live with so much that they want to kill you... because you need to sleep and when you do, you might get killed.
And the "ecchi" part in the previous chapter basically said "Yo, I'm Japanese and these guys have a different culture. I'm da reincarnator."