Two people have the same birthday, which should be father and son or brother. Moreover, in the cartoon, it is also shown that Arima Kisho will be a person suspected of Jin Mu Sasaki. According to Arima Kisho's analysis of Jin Mu's revelation in "Tokyo Ghoul", it is likely that Arima Kisho brought Jin Mu to the search office, which is definitely impossible if it has nothing to do with it. After all, all the species I have seen with Arima Kisho are dead, and Jin Mu can be taken to the search office by Arima Kisho himself. It's just that the sun is angry from the west!
Apart from the watermelon brain hole, two people must be related by blood!