Who was the last person in the castle to write to Klein?

In the part of "Lord of Secrets", Azk Eiges finally wrote a letter to Klein in the castle with two spells of "yesterday reappearing". Once used, you can find your past self from the pores of history and borrow strength from him.

The Lord of Secrets is a western fantasy novel written by a platinum writer of Reading Group, a squid who loves diving. It combines Cthulhu style, western magic elements, the style of the first industrial revolution and the feeling of steampunk.