Ayase Kuze

Ayase is Aburaya childhood friend but the real Ayase died and the double of Ayase was pretending to be his childhood friend but she started to had feeling for him and died when she told him that she wasn't the real Ayase and try to tell him her real name.

Then in Chapter 4 another Ayase from the same organization enter Aburaya life but this is Ayase is more cold hearted and doesn't care...But it seem their were more copies of Ayase waiting when the other one dies their main purpose is to make Aburaya have a normal life and keeping an eye on him.

(Source AkatsukiUlquiora)