For this particular Time Traveler with a bizarre codename and no known specific name, Fisher had no clues to trace him. He only knew that the man seemed to have a fondness for demi-humans... Wait, if this guy also liked demi-humans and even wrote a Completion Manual, it at least indicated that he had made contact with virtually all demi-humans, many of whom are of the Longevity Species, similar to the Whale-man Species.
It was very possible that some of those Longevity Species had encountered a human who shared their special interest in demi-humans?
Perhaps a member of the Demon Species might know, but Elliog was far too lazy, always sleeping in the Abyss, so it was unlikely he knew anything. Emhardt, who was terrified of Paimon, was much more likely; or Moli's mother, Xuan Can, who also seemed to have lived a long time... Fisher didn't know many Longevity Species so far, so he figured he could check with the Longevity race when he met them later.
