Responses
Yes.Grey and Aruse are the same person
Here it's Aruse http://www.mangago.zone/read-manga/ibitsu_na_koi_no_seesaw_game/uu/ibitsu_na_koi_no_seesaw_game-chapter-5/41/
And In the next page he puts his Grey persona wig and he has the three moles http://www.mangago.zone/read-manga/ibitsu_na_koi_no_seesaw_game/uu/ibitsu_na_koi_no_seesaw_game-chapter-5/42/
Oh please don't tell me this is the end...I still don't know whether or not he is actually Aruse! ;-;