Years ago I ran a homebrew campaign that I called “The Crystal of the Ebon Flame.” The campaign was of course based around the artifact of the same name, which I had seen in a First Edition Dungeon Master’s Guide. I just used the name, which I thought was really evocative, and created the details of the artifact myself. I set my campaign in the Forgotten Realms, and decided that this artifact had been crafted long ago by the gods Bane and Myrkul. It gave its wielder the power to command large numbers of undead and evil humanoids, and was able to unleash soul searing bolts of power at nearby foes. It had been designed primarily as a weapon of war.
I’ve always been very revisionist as a dungeon master, taking what I like from a setting and rewriting other things as I saw fit to tell my story. To this end I decided that the Crystal of the Ebon Flame was used by the forces of darkness during the fall of Myth Drannor. At the height of this conflict, the avatars of Bane, Myrkul, and Corellon Larethian, among others, were present on the field of battle. Corellon Larethian managed to strike the Crystal of the Ebon Flame with an arrow at a pivotal moment, sending it flying from it’s wielders hands and causing chaos to fall upon the ranks of the wicked. Myth Drannor was ultimately lost, but this respite from the awful power of the Ebon Flame was enough to allow the elves to rally and rout several of their enemies. Priests of Bane and Myrkul managed to spirit away their foul artifact to a temple fortress but the elves, too weak to mount an assault on this fortress, were nevertheless able to seal their enemies away in this fortress with powerful magics.
That was all developed much later than the first adventure. The game started as a one-off adventure with a few friends. The adventurers were sitting in a tavern (original, right?) when some local miners came in complaining that undead had begun to pour out of the new shafts they had opened up. The hearty adventurers rose to the challenge, driving the undead back and exploring the ancient worked passageways that the miners had uncovered. The passageways eventually led to a large door that was shielded by a powerful force that they were unable to breach. And that is where the adventure ended for awhile.
Eventually I picked the idea back up again, and fleshed out what this giant door was and why it was sealed (see above). The ensuing campaign lasted for several months, during which my party adventured from Coromyr, to Myth Drannor, to the Sea of Fallen Stars, racing the forces of the Zhentarim in an effort to prevent their foes from unlocking the magical door. The campaign culminated in a giant battle west of Tilverton, where a brave elf in our party paid the ultimate price to destroy the Crystal of the Ebon Flame forever by becoming a conduit between the Prime and Negative material planes so that the magic of the flame could be siphoned into the void.
All of this happened with none of the party members being higher than 8th level (A dwarven fighter named Gobo Stonebrow, the only character to survive from that first adventure all the way through to the end), proving that you don’t have to be a demi-god to save the world. I made a lot of the adventures up just a few steps ahead of the group, and always felt like I’d like to run it again someday, since it felt like a rough draft more than a polished campaign in some places. I doubt that will ever happen, though, since I’ve lost a lot of my notes from back then. My memories of those adventures are probably better than trying to relive them would be anyway.