Orc Knight
Auror
The relevance of the title question should be answered shortly, as long as I don't ramble. This is more an exercise in world building and the consequences of past events that may have tore through your fantasy world rather like an ogre through a pie eating contest.
To the original question in answer for my world of Eld is fairly simple. Undead almost took over the world and nigh on destroyed it, leaving it in the post apocalyptic fantasy it is. One of the consequences that came of it was that across pretty much all societies (there's always those hold outs that won't change their traditions even in the face of such things) stopped burying or entombing their dead and what was once held sacred had to be changed. Burning bodies was simply the consequence of it and some thought rather paranoid after they believe the threat is gone (spoiler: It's not.). It keeps the threat at bay and makes it harder for the Liches to bring back massive armies to raise hell across the world again.
So, in this exercise, if anything like this has happened in your world and story's, does it have some fairly lasting consequences? True, it may not show up, but you know what it is even if the audience doesn't.
To the original question in answer for my world of Eld is fairly simple. Undead almost took over the world and nigh on destroyed it, leaving it in the post apocalyptic fantasy it is. One of the consequences that came of it was that across pretty much all societies (there's always those hold outs that won't change their traditions even in the face of such things) stopped burying or entombing their dead and what was once held sacred had to be changed. Burning bodies was simply the consequence of it and some thought rather paranoid after they believe the threat is gone (spoiler: It's not.). It keeps the threat at bay and makes it harder for the Liches to bring back massive armies to raise hell across the world again.
So, in this exercise, if anything like this has happened in your world and story's, does it have some fairly lasting consequences? True, it may not show up, but you know what it is even if the audience doesn't.