Jason Blood was a Crusader Knight from Camelot. In order to save his life, Merlin bound his essence with that of Etrigan, so as to save his life and this rendered him immortal.
In the times of King Arthur, he is bound to a mortally wounded Jason Blood by Merlin to defeat a malevolent sorcerer named Destiny.
All over the world, people suddenly begin panicking as they start to see everyone around them as demonic monsters and end up killing innocents before members of the Justice League stop them. Deliberating about this strange outbreak, most of the League's members come to the conclusion that magic must be involved in this. Despite his own past experiences with magic, Batman expresses his skepticism and walks out; but as he returns to Wayne Manor to rest, he suffers a temporary blackout (from a possession by Deadman) and then finds the word "Constantine" written all over the nearby walls.
One day John Constantine and Jason Blood – engaged the Demons Three in a poker game in Las Vegas for high-end stakes; the former even offering his home, the House of Mystery, as his part of the pool in exchange for a box of artifacts, including one called the Dreamstone. However, both parties cheated at the game, and when Constantine exposed the Demons' trickery, they attacked him. Constantine unleashed Jason's alter ego, the demon Etrigan, who defeated the Demons Three, but not before they swore revenge on him.
When Deadman, Batman, Zatanna and John Constatine visits to Ritchie's home to identify the ring from the man's memory, the team finds him about to die, with Blood nearby. Batman revives Ritchie with an adrenaline shot to the chest, but he quickly falls into a coma. After being brought to the House of Mystery for interrogation, Blood tells the team that he did not attempt to hurt Ritchie, but was looking for a way into the House of Mystery to find the Dreamstone. He reveals his past and Destiny.
The group locate Faust's observatory with help from Swamp Thing. When they infiltrate Faust's lair, the wizard battles the team, but is ultimately defeated by Zatanna; however, Faust is found to have no involvement in hurting Ritchie.
In the course of the final fight against Destiny, he and Blood are separated again by Destiny. Jason slated destiny with a sword.
Right afterwards, Blood succumbs to his mortal wound from centuries before. He peacefully passed away before saying goodbye and thanked the Justice League Dark. Zatanna, Constantine, and Etrigan bury Blood's body near the place of his old village. After helping in Blood's burial at his old village, Etrigan departs, revealing that due to their long bond he has come to respect Blood.
Powers and AbilitiesEdit
- Swordsmanship: As a Knight Crusader of Camelot, he was remarkable swordsman and fencer. He lasted the longest against Destiny.
- Occult Knowledge: He has a great deal go knowledge about the supernatural world.
- Immortality: As long as he was bound to Etrigan, he was an immortal cannot die by natural means. He has lived for 500 years.
- Accelerated Healing: Upon being bound to Etrigan, he healed from his wounds instantly. However, after Etrigan and he were separated once again, his wounds returned and he died from them.
- Transformation: He can switch back and fourth from his human form and Etrigan the Demon.