So, Rintaro-sensei’s first best friend was Haruaki-sensei all along.
When they were children, Rintaro-sensei and Haruaki/Abe-sensei met—possibly in a forest, though it’s not entirely clear where. In the main story, Miki-sensei invited Abe-sensei to his house to use him in exorcising his mother. This ties back to Miki-sensei’s tragic past: his mother had eaten his childhood friend, who turned out to be Haruaki-sensei.
In one of the extra chapters, it’s revealed that Miki-sensei’s older sister brought a sack (containing a dead body), a light stick (used for rituals for the dead), and some death-related ornaments to the forest. From this sack, the child version of Haruaki was revived, but he had lost all his memories.
This is my theory for now—I’ll reread the story to understand it better.
So, Rintaro-sensei’s first best friend was Haruaki-sensei all along.
When they were children, Rintaro-sensei and Haruaki/Abe-sensei met—possibly in a forest, though it’s not entirely clear where. In the main story, Miki-sensei invited Abe-sensei to his house to use him in exorcising his mother. This ties back to Miki-sensei’s tragic past: his mother had eaten his childhood friend, who turned out to be Haruaki-sensei.
In one of the extra chapters, it’s revealed that Miki-sensei’s older sister brought a sack (containing a dead body), a light stick (used for rituals for the dead), and some death-related ornaments to the forest. From this sack, the child version of Haruaki was revived, but he had lost all his memories.
This is my theory for now—I’ll reread the story to understand it better.