I read it as an assignment that still has to be carried out, i.e. neither of them are dead yet but people believe it will be done by women.Hey I can't believe I didn't catch this part. Casimir and Ibrahim are gonna get killed by women, possibly Roman women in this very war.
Which of course reminds us of the "curses" Demetrios III put on them. The question is how do people know about that? Did Demetrios publish his drunken ramblings as propaganda/prophecy?