Crossover Fanfic: X, His Sister!

[I'm proud because my IQ isn't especially low, and my EQ isn't especially high.] Voiceover: Your IQ isn't especially high, and your EQ isn't especially low, either. [...] Actually, this is the story of a girl who transmigrated N times, got so numb to it that she stopped feeling sad, homesick, resentful, or bitter, and quit blaming the world or thinking everyone owed her something. She was about to transmigrate for the N+1th time, but every time she did, she ended up as X's little sister. [Fill in X yourself.] Each world is short, but there are lots of them, and they'll cover all sorts of things. There might be multiple love interests. If that's not your thing, click the red X. Please don't throw bricks, or eggs. P.S. Our girl is extremely badass, inside and out.