@Stormdragon
I forgot about her being at the fire...but I still don't think she really understands what all was going on
she may have been in on the throwing Leslie into the fire part of the plan, but based on chapter 1, it sounds like daddy told everyone it was because "Leslie had to die in place of Eli" because "destiny" reasons and not "we're sacrificing Leslie to make Eli stronger" so Eli most likely did NOT understand why that all actually happened...and it was daddy yelling they weren't throwing Leslie in fast enough
as for Eli complaining about her powers being too weak, that's probably just a combination of the expectations her family pushes on her and the end result of the family's decline (which I personally suspect is due to a weakening of the blood-line given they have a formal ritual to sacrifice anyone born strong so the weak "pretty" ones can steal that power...but since it isn't their innate power they have progressively less chance of children with strong powers being born)