Welp the little sister type obsessed with the heroine that hates the male lead is a trope that still rears it's ugly head to this day.
Ah well it's not like our heroine is forced to stay inside. Like the MC says she goes out when it's unnecessary for her to but he doesn't really get on her case about it. Also he's not forcing her to stay inside she does that herself for the most part. If she really wanted to go outside I'm sure she could ask the MC she wants to go outside.
With all that said her personality is terrible but she's a young angel so I kinda give it a pass. She's also very cute.
for all that what you said is true, she also seems like someone with common sense in terms of the existence of human malice.
Meaning the ban on angel going out alone, could be solved by letting the brat act as her handler and guardian.
I read the chapter, and I think, "lol, Towa's little sister is cute and funny." Of course, the kusogaki sidekick who hates the MC is a romcom cliche, but so is everything else in this manga. That's not a criticism. I read tropey supernatural romcoms because I like them. And I like Shiu, bad personality and all.
Then I come here and find all these idiot creeps talking "cunny" and "bitch", fantasizing about killing her. And it's like