Jason Blood aka Etrigan the Demon is one of the supporting protagonists in Batman: The Brave and the Bold.
He is voiced by Dee Bradley Baker.
During the time of Camelot and King Arthur, the sorceress Morgaine Le Fey attempted to usurp Arthur's throne. Merlin bonded a traitor named Jason Blood to The Demon Etrigan, Rhymer class, the half brother of Merlin and last line of defense of Camelot. Le Fey's magic proved too strong and she took control of The Demon. Merlin later freed The Demon from her control. When Le Fey was defeated, the Demon teleported away.
After Merlin's spell was broken, Jason Blood and Etrigan decided to continue to be in his service and fought Le Fey at least once more. In the 1500's, the trio teamed up to face the demon prince, Asteroth. Asteroth was attempting to leave the underworld and take over the mortal world. Merlin and Etrigan used Wagner's Horn to permanently trap Asteroth in the underworld.
300 years later, Blood was settled in London and garnered an infamous reputation for being a madman obsessed with the occult. Meanwhile, Gentleman Jim Craddock was gathering ten human souls and framed Blood in order to complete his task. In desperation, Blood tried to cast a spell to teleport Batman to his time. Before he could finish, an angry mob burst into his lodgings and bound him with iron handcuffs and planned to burn him at the stake. After discovering the culprit was right handed and Blood was left handed, Sherlock Holmes completed the ritual and teleported Batman to the past.
Blood and Etrigan were convinced that Asteroth would betray Craddock somehow and tried to reason with him. When that failed, Etrigan knocked Craddock unconscious and attacked Asteroth while Batman grabbed Craddock's iron cane. Etrigan quickly threw the cane into Asteroth's open mouth. In the occult, iron is a metal with life-force and could bind and even kill supernatural forces. Asteroth crumbled to dust instantly. With Blood's name cleared and Craddock in custody, Blood returned Batman to his proper time.
Jason Blood and Etrigan are still active in the 21st century. They teamed up with Batman to track down Dala, a woman turned into a vampire by an affliction created in a laboratory. Blood utilized a device that could track a distinct energy signature given off by vampires. After Dala was neutralized, Etrigan set off on creating a cure. Upon realizing Batman was bitten, Etrigan later teleported to the Watchtower and helped Martian Manhunter restore him and the rest of the League back to normal. When Batman awoke, Martian Manhunter and Jason Blood were at his bedside to inform him of his poisoning.
- The Siege of Starro!, Part One (cameo)