A long, long time ago, there was an evil spirit, Mormo, who fed on human blood. But no matter how much she drank, she could never satisfy her thirst. Restless and desperate, she decided to descend to the Underworld and feed on human souls, hoping that their essence would extinguish her craving once and for all.
She managed to sneak past Cerberus and reached the banks of The River Styx, but could not cross to the other side without the assistance of Charon, the ferryman of the dead. Mormo tried tricking Charon, pretending to be one of the dead. But the coin she gave him wasn’t made out of bronze, like the ones mere mortals would give him, but of silver. Charon recognised Mormo and cursed her, saying:
'Let silver be the demise of you and all your kin! Let it burn you just as hot iron burns thieves and liars.'
And from that day on, Mormo and all those who feed on blood hate silver, and they will hate it until the end of time.