Reaper

Most of what is known about Reaper can be put in one of two categories, guesses and myth. There are several stories detailing where Reaper came from, each one worse than the last. Some say that Red Jack found him in the swamps being raised by wild animals, which explains his savage and bloodthirsty behavior. Others say that he lost his mind from years of torture before murdering those who had kept him hostage. Lastly, some say that he isn't even from here, that he is some sort of horrible creature from the Shadowfel that somehow stumbled upon this realm. This one has gained traction as no one has ever seen his face and lived.
What little is known about him does little to shed any light on who or what he might be. Even his exact race is uncertain as he always wears a long black cloak with a hood and black leather gloves on his hands. He is around 6ft tall, which rules out many of the smaller races. He doesn't have any sort of horns or protrusions that would suggest dragonborn or tiefling no tail to indicate tabaxi.
Reaper was a part of the Red Jack Nomads, though is exactly rank within the gang was never certain. He was part enforcer, part guard dog, and all terror. He was seen as a mad dog that only Red Jack was capable of controlling. When Red Jack was killed, Reaper initially accepted Saber as the successor. Once Saber was captured, Reaper then took control of the gang. He led a crusade against those he felt had wronged him, or wronged the gang. The rest of the gang followed him out of fear, but soon he lost all interest in attempting to lead anyone. He left the gang and seemed to vanish into the night. He hasn't been seen or heard from since, but his name continues to strike fear into people's hearts.