That means the girl in the teacup knows the current him.
As an exorcist with a small reputation in the area, that's pretty normal.
But...
Don't forget this diary!
Recall 'his diary'!
Full of traces arranged by someone else.
It's filled with pursuits, secret investigations, revenge, and the like.
If it were Jason himself, if he really went through all this and sought revenge, he would certainly do so covertly, and not so 'ostentatiously'.
Even ordinary people could find their way to him.
"Indeed more troublesome than I thought!"
Jason was skeptical about the real use of this diary before.
After all, who writes diaries seriously!
Who can write down their innermost thoughts in a diary?
What's written cannot be called innermost thoughts.
Maybe, Jason is judging others by his own standard.
'He' might have other purposes in doing this.
For example: to lure the snake out of the hole.
And according to the end of the diary, 'he' did quite well.
