The Villain to your Heroes

BLACK OMEN
A powerful foe not to be trifled with. He wields a deadly weapon called the Omen Blade. You can run but you can't hide, BLACK OMEN will find his prey. His evil presence can be felt wherever he travels. Adventurers who crosses path knows to avoid confrontation. 

OMEN BLADE
An ancient evil spirit was trapped inside this sword long ago, cursing it. Once the Omen Blade has drawn blood from its victim, the victim will never truly heal from that cut. Causing pain where the wound is. It also marks its victim, allowing Black Omen to sniff out his prey. Like a GPS, the curse wound will call out to BLACK OMEN like a beacon where ever how far.
The only way to rid one of this curse is through an ancient ritual that has been forgotten.