If the younger sister wants it, the younger sister will get it.
If the younger sister doesn't want it, the younger sister can't get rid of it.
I tried my best to write it in detail, but it is still a half-brained outline.
Ooc apologizes
The parallel world timeline does not exactly follow the cards.
The girl in the setting is a bit scumbag and a bit strong.
There is no explosion in the parallel world, but there is another male protagonist (=′ー`)
Yes, I am all pusher brother fish
Intention: Be a good person