Okay was not expecting the shift

Without checking the tags, summary or comments I just went straight to reading and the way I was shooketh by the mother's entrance in chapter 9. I was seriously reading this thinking it's a cute manga between an extrovert and introvert slowly becoming friends and maybe more later on but damn I wasn't expecting the dark psychological shift. I'm really amused by it and this makes the storyline more complex and interesting to read so looking forward to it!