Esther summonses ‘Hassach.’ She commands him to go to Mordechai. ‘Hassach’ is Daniel. But Hamman killed him and he was unable to finish his mission.

What’s Daniel doing in the story of Purim? Why is he referred to as ‘Hassach?’

Sources:

Divrei Pinchas from Rabbi Pinchas Friedman of Yerushalayim.

Megillas Esther Perek 4 Pesukim 5 - 12

Shir Hashirim Rabba Parsha 7 Chapter 9

Kassem Ofir on Megillas Esther

Megalleh Amukos Parshas Vaescganon (Oifan 195)

Yaaros Devash Chelek Aleph end of Drush 3

Gemara Berachos 61 B