The Blood are a group og beings that came together before Atlantis, serving as allies to the original Spirits of Vengeance. Their primary purpose was to guard the Medallion of power and keep it from being like Zarathos, Who sought to use the Medallion for their own purposes .
When Zarathos succeeded in temorarily gaining possession of the Medallion, The Blood united with the Spirits of Vengeance and mounted a last-ditch effort to retrieve the Medallion. During the battle the Spirits of Vengeance where trapped along side Zarathos in the Medallion of Power. The Medallion became so powerful that no one individual cocould be entrusted with it, The Blood decided to brake the Medallion in to pieces and place bound them to the souls of two human families. One of the eldist members of the Blood was given the ask of watching over the two families, he was named the Caretaker.
After these avents the Blood started to splinter and go their separate ways, some begain to worship Zarathos, they became known as the Fallen. Some went into hiding in the most remote parts in the world and would only come out when called these where known as the Hidden. the remaining members of the Blood apointed Regent as their new leader.
After Lilith and her children revived Zarathos, the Blood once more came back together but they could not beat the combind forces of Zarathos and his followers, so like they did all those years a go they allided themselves with The Spirits of Vengeance but this time it came in the form of Ghost Rider [Dan Ketch] who was also part of a team intent on stoping Zarathos, The Midnight Sons.
They manged to defeat Zarathos and the Fallen but it came at a cost, many of the Blood had died including two of the eldest members Embyree and Raydar. The remainder of the group once again went their seperate ways and went back into hiding waiting to be called up on again.