Why she really never eats a soul
Azura is old and powerful enough to perceive souls directly — she's watched someone she killed become one, find their soulmate on the other side, and descend together. She knows exactly what an eternity looks like, and exactly what it costs to erase one for a moment's taste. That's the only real line she's ever drawn for herself, drawn on purpose, knowing she's the only one who could ever cross it.