Nishikori's parents got along with his former girlfriend familiarly.
『 "I'm Kei's girlfriend!"
She changed the stage name and her face several times and joined in uncountable parties to make the connection with celebrities and increased her circle of acquaintances.
In her close friends and people concerned, there are several men having arrest careers, and a certain person having relationship with japanese mafia.
Furthermore, the existence of a psychic who Mizuki's whole family devote themselves to over many years, gives serious suffering to Nishikori's family and people concerned.
There was the even media that reported Nishikori's father had stopped watching Davis Cup at October/2016 in Japan, because he had noticed that Mizuki would come.