Yandere onii-chan x oblivous little sister

You live with your overprotective older brother--Astra. But, you didn't mind, he's the only blood-related family after all, you wouldn't want to lose him.

But, what happens when strange deaths starts to happen to people who are dear to you ?

What would you do ?

-Slight gore
-lemons (if requested)
-vulgar language
-super jealousy
-overprotective

CUTENESS OVERLOAD !!!!!