It seems that those who become "monsters" lose their memory which is probably why the society haven't accepted them in the fist place. Since they were carving for souls but didn't care for anyone they became monsters for those around them.
At least that's what my conclusion is.
The teacher changed because of Shiva and doesn't bring as much attention to her soul. Shiva is changing him and making him capable of feeling.
Remember? Monsters aren't supposed to feel. It was mentioned in one chapter. So the teacher is an exception but grandma is just a regular case like all the other monsters.
i know. i got that idea as well. i have mixed feelings about this tho, i love how teacher is becoming more like shiva <3 but i am sad about how shiva will react to her grandma not recognizing her as shiva anymore and only as a soul. (╥﹏╥)
who is this mother really?? and why does shivas grandma turning into the "Monsters" more like them and teacher turns into someone more like shiva?? (╥﹏╥) so confused i want to know more ! <3