There is a crazy thing in this scene. Pictures From the left to the right are: The AL of Dr. Nicolaes Tulp, Saturn eating his son and The kiss. The relationship in 3 pics respectively are: Teacher - Student, Father - Son and Lovers.
It can be thought in a simple way that Khoa just loves all those pics and put them there or maybe It is a darker idea of phantomghost relationship. I love the way Ed put ancient art in comic too. It took me lots of time to find out but satisfy about it.
Moreover, in the batman inc tpb the place Khoa keep phantom is changed from oslo to stockholm, Sweden. This is the right place cuz Oslo is not in Sweden. This place makes me think about Stockholm syndrome that the People develop positive feelings toward their captors or abusers over time. Yes I mean Phantom-one does love his father and he seem to love Ghostmaker more than normal. He did not care about Khoa killed his old parents. He is just angry cuz Khoa could not save him. He used to think they even had kinship. This boy is crazy af believe me. There are so many details in batman inc Arc 1 to point out this if you try to focus. It seems like Khoa just adopted a psychopath too:))
