The Dragon Hunters are one of the two main antagonistic factions (alongside the Sons of Garmadon) of Season 9: Hunted and minor characters in Season 10: March of the Oni in LEGO Ninjago: Masters of Spinjitzu.
They are a civilization who inhabit the Realm of Oni and Dragon. With Iron Baron as their leader, they hunted, enslaved, and presumably feasted on Dragons for years.