Heinkel doesn’t have any known aliases in canon, so I used a random Austrian name here.
Robin: “Doesn’t exist”? I thought he just entered the country.
Michael: No, someone with his name on a passport entered the country.
“Oscar Wiesenthal” is a known alias of one of the Vatican’s agents. Real name Heinkel Wolfe. Age and gender unknown. If he or she is sneaking into Japan, that means the Vatican is on a secret mission. Probably after a witch.
Robin: I didn’t know they were allowed to do that.
Michael: They aren’t.