Angels and the demons have been in eternal conflict to decide who is dominant and this shall never change. Angels cannot exist without demons and vies versa. They exist to keep the balance in worlds, but in the last 1000 years the demons have become greedy. They have been controlling humans and using their body's to harm others to create the chaos they feed on. The angels tried to stop it but the vows the made when they became angels stop them from harming humans. The demons used this to their advantage and grew stronger.
This carried on for years until 100 years ago the queen of the wolf sisters tribe had a vision that the battle would be won by six females and six males forming the protectors of the heart. Each one represented an element of fire, earth, air, water, music, technology, nightmares, death, animals, mind manipulation, energy and weather. These 12 heroes will all be the same age and will be the ones who will save all the worlds. They will go down in history, but visions are not always set in stone. The prince of the snake brothers tribe had a vision about them too, he envisioned them becoming the destroyer of worlds and enslaving the rest. This caused a war between all the tribes half taking the wolf sisters side and the other half taking the snake brothers side. The ones on the wolf sisters side vowed to protect and train them, while the ones on the snake brothers side have decided to capture or kill them. This ended up causing a rift in the tribes allowing the demons to train, gain members and just cause chaos while the tribes fought amongst each other.