I mean... look... maybe it's the Axe of Dekeron, said to have been forged in Hell itself. Lost since the Children's Crusade, where it killed a lot of... oh... children. I hope that's not it.
Willow Rosenberg[src]

The Axe of Dekeron was a mystical weapon said to have been forged in hell itself and lost since the "Children's Crusade", where it was said to have been used to kill children.