“Who is he and where is he who dared to do this?” (Esther 7:5)
The Apter Rav notes the following in his sefer Ohaiv Yisroel:
The Megillah says that Esther requested that the king spare her life, that her people were sold to be destroyed (nimkarnu l'hashmid). Why the language “we were sold” - should it not have been “we were decreed for death”? Secondly, why does Achashveirosh say: “mee hu zeh, v'ay zeh hu” - who is behind all this? Surely, he was aware of the decree; he himself signed it “v'yichtov b'shem hamelech"!
R' Sherira Gaon relates a ma’aseh that happened: There was a rich man who owned a sefer Torah that was written by Ezra HaSofer. Upon his death, his 2 sons both desired to possess it and the local beis din paskened that a drawing would be utilized to determine who would obtain it. The winning brother was elated; the loser was dejected, notwithstanding that he received other material riches instead. A local mumar [heretic] was angry that somebody would prefer a Torah over riches. Therefore, he disguised himself and went to the shul housing the sefer Torah. At night, when all had left, he took out the sefer Torah and opened to the phrase “v'avadtem es Hashem, u'vayrach es lachmecha” (you shall SERVE Hashem) (Shemos 23:25). He erased the letter “ayin” in “v'avadtem” and replaced it with the letter “aleph”, changing the meaning of the phrase to a blasphemous statement (the word for “serve” became “destroy”). When the “mistake” in the sefer Torah was discovered, the owner was shocked and hurt that even if “corrected”, the sefer Torah surely must not have been written by Ezra HaSofer. The deceased father came to this man in a dream and revealed to his son what had actually occurred. The father told the son not to have the sefer Torah fixed, because it was decreed in heaven that Ezra himself would go and fix the “error”. In addition, the father told the son to go look under the shulchan and there he would find the actual “eye” of the mumar, as “ayin tachas ayin” -- the mumar took away the “ayin” of the Torah, so his “ayin” was taken away (an eye for an eye). As the father said, so it was.
Based on this, we can answer our initial questions. Originally, Haman approached the king by saying only to enslave the Jews, bribing the king with 10,000 kikar of kesef. The king agreed to this and a shtar mechira [sales document] was drawn up in lashon hakodesh [Hebrew]. The king signed this decree and Haman took it to the scribes for transmission. However, before the scribes received it, Haman erased the “ayin” of the shtar's requirement of servitude “l'avdam”, and replaced it with an “aleph”, changing the meaning of the shtar to one of annihilation (“they shall serve” became “they shall be destroyed”). (The scribes elaborated this theme and added “l'hashmid, l'harog, v'laavad”- they shall be killed.) When the king finally was confronted with Esther's pleas for mercy, Esther said that the Jews were originally aimed for slavery “nimkarnu”, but now they were aimed for death (maybe she knew this with Ruach Hakodesh or maybe Haman's “original” plan had been public knowledge). The king honestly asked “mee hu zeh?” Who decreed death on the Jews? I only decreed servitude! That's why he was surprised to learn about this death decree on the Jews - he didn't even know about it! (R’ Daniel Lasar)