
Grey is very clearly Aruse. As Sudo said, three aligned moles is very rare. The fact that they're on his neck too in the exact position Aruse had them is incredibly suspicious. You don't just find someone like that by chance. Not to mention the fact he knew the events in Aruse's life and the fact that when Sudo and him were talking about sex, Grey said "you wouldn't sleep with me back then." Also, if you remember carefully, back when it showed the flashback between Sudo and Aruse, you may be able to recall Aruse saying "I hate being indebted to people.", a quote Grey has mentioned in this chapter, too.

shipshipshipshipshipshipshipshipshishipshipshipshipshipshipshipshipshipshishipshipshipshipshipshipshipshipshipshishipshipshipshipshipshipshipshipshipshishipshipshipshipshipshipshipshipshipshishipshipshipshipshipshipshipshipshipshishipshipshipshipshipshipshipshipshipshishipshipshipshipshipshipshipshipshipshishipshipshipshipshipshipshipshipshipshishipshipshipshipshipshipshipshipshipshishipshipshipshipshipshipshipshipshipshishipshipshipshipshipshipshipshipshipshishipshipshipshipshipshipshipshipshipshishipshipshipshipshipshipshipshipshipshishipshipshipshipshipshipshipshipshipshiship
LET ME TAKE SHELL'S PLACE
LET ME TAKE SHELL'S PLACE pLAESe
HIM AND ERIC DESERVE A HAPPY ENDING THEY'vE WORKED SO HARD FOr IT