When you kill Ethel and talk to her corpse using magic she hints at being able to resurrect herself, so she will probably become important again later.
Going to repost this so more people see it. Normally I would not evangelise Larian's grand vision in storytelling but there is some heavyhanded foreshadowing that;
We will meet Ethel's Fey sisters in Baldur's Gate and that Ethel herself is going to come back in Act 2.
