Don't worry, this manga ends at chapter 19 (probably got axed) and i'm not gonna spoil anything but if you want to know if the ending will gonna be happy or tragic :
the ending is a happy one.
If you can read in Bahasa (Indonesian language) here's the link : https://mangadex.org/chapter/540500/1
I was about to call this the shittiest wish-granter/monkey's paw ever, but Tsurara did this with her own motives in mind, which actually makes this more explainable.
This manga's pacing is speeding up a lot, definitely feels cut short. We didn't get to properly explore characters like Kanai, and the Volleyball girl. Weird to think this guy made Kawaii Joushi wo Komarasetai too. That story is max comfy.