Most of the letter was handwritten by Needham Brown, with an additional printed paper explaining a few things.
Previously, Harrison Clark had learned about four Informed Guides from Star.
The first one was Emmanuel Berto, the second was Bernal Connor.
The fourth was Horatio.
"The fourth and final Informed Guide is Horatio."
These were Star's exact words, subtly skipping the third Informed Guide.
After Horatio, no more Informed Guides were born.
Harrison knew all these.
But at that time, he subconsciously neglected the third person.
Perhaps it was due to the large amount of information he had to absorb in a short time that he overlooked these unimportant details.
Or maybe the thought briefly flashed through his mind, who was the omitted third person?
It must be an unremarkable minor character, whose name happened to be remembered by him.
Since Star didn't mention it, it probably wasn't essential.
Now he knew the identity of the third person.
It was Needham Brown.