Atsushi finally coming to terms with the fact the director of his orphanage is in the past. He plagued his childhood, reappeared in the form of flashbacks that terrified Atsu in his adult years. Now? Hes dead, with our main character accepting that the memories were his minds own doing and hes in charge of them, letting him shape them however he wants. In the past, the image of the director was brought up almost as a warning for atsushi to stay cautious, then we witnessed Atsushi learning to use it as a motivation (the chapter where they pushed a gate open, getting to Ueda), and recently ehat i believe was just wanting to feel peace. (the panel with kid Atsushi and the director on a picknick)
Now hes just a memory. Hes dead for good, and combined with the character development Atsushi had gotten these last chapters I dont think we'll be seeing his abuser in the future.