When I Went to Another World, My Little Sister Was Already Reigning as the Demon Lord - Vol. 1 Ch. 2 - A Stroll

[MangaDex]

 

[HoangDinh]

hello? Is there more?

 

[KinshinReaper]

God she's fkn annoying. Her personality towards her brother after all this time is enough to drop.

 

[Khri_na]

God she's fkn annoying. Her personality towards her brother after all this time is enough to drop.

And that's the most standard "tsundere lil sis" you'll find in early 2000, where violence is considered normal (for some reason) for any type of tsundere character.
It's just like a "hard to keep and selfish Chihuahua that bites", people just had preference .