stonegod
Spawn of Khyber/LEB Judge
There was no Realms-Shattering-Event (TM) 3e->4e. The Last War and the Day of Mourning are all core elements of the Eberron setting. The transitions actually didn't even advance the timeline (an earlier idea that had significant backlash against it).Oh! Awesome! For some reason I thought the Last War was still going on during 3e. This is apparently what I get for skipping an edition. I'll go digging through what I've got at home.
Chief thing to remember about the Day of Mourning: Officially, there is no explanation. While home DMs are allowed to provide the One-True-Reason (TM), WotC has promised (for now) that there will not be one from them. As for Living Eberron, I believe we should keep this policy. While there may be many theories, I don't believe we should canonically establish One-True-Reason.