@WanderingSpectator If I'm reading it correctly, Eli only passed the first part of the test(with bribes) when she broke her leg, and couldn't do the other test. So they only said she was a candidate to be the priests; nothing about who was/would be Arabella, but its also likely it is recommendation-based. The Empress believes that Leslie will win anyway, but it doesn't matter to her. What the empress is trying to do is to simply remove the plague box from the special room and bring it out into the open. Its what Acela wants too, but because of the message the Empress sent her, she now has to decide if she's gonna have Leslie get the box(which would supposedly kill her
[we know it won't since she fMC]) and prevent it from falling into the Empress' hands to halt her ambitions, or let Eli do it, which would put the box in the Empress hands. We still don't know what it can do, but it can be assumed that the Empress has much more knowledge on how it works, and probably only needs it to be removed from the room to use it in any capacity, but since Acela doesn't know that, that's why she wanted Leslie to be Arabella.