Nerdsplaining the difference between shadow elves and drow does not answer my question to @Kobold Avenger. He says that he thinks shadow elves were subsumed into the shadar-kai elves in 5E, and I was asking where that reference was from. From my own post, I hope it's clear I have a grasp of the shadow elves of Mystara.Aside from living arrangements, shadow elves and drow have nothing in common. Shadow elves have no real special rules aside from a boost to dark vision below ground, they don't even suffer from being above ground and certainly don't get bonus spells. The biggest difference between them is that most people don't even know the shadow elves exist because they are isolated. And for the ones that do find out about them, they don't care. They were given a line of balderdash by their leaders to make them hate the surface elves, and the threat of that lie being exposed is a major plot point to their background.