Demons, Gods and how they came to be.

When time was new and Akara newer, demons crawled their way through the veil and entered a new plane. This plane was bright and green and rather empty. The demons hated this new plane, they sought only chaos and fear to feed upon. They tried to make the plane similar to their own but couldn’t interact with their surroundings nor could they stay in the new plane for long without bodies. It seemed the material plane was safe from those who brought chaos.
Then the first demon met a human. It seemed nothing more than a confused conversation to both until the demon placed a hand upon the human. The demon could feel the human's very soul and pushed it down and took the body. With this new ability, the demons gained a foothold in Akara. Nothing but Chaos and darkness followed in their wake.
It was this way for thousands of years until the Gods moved beyond their own veil in the Proven Fields. They saw the fear The Daemonium brought and the pain of the humans, and the kind creatures they are, they rallied both the Proven fields and the humans of Akara to stand against the demons. A handful of Gods chose human champions to fight and imbued them with gifts of heaven to help turn the tide of the fight.
Angels, Champions, and Gods alike waged war against the Daemonioum to bring peace and order back to Akara. The battle was hard-fought and took years but the Gods emerged victorious and sealed the demons back to the ethereal plane of the Agony Grounds .
The champions of the Gods went on to continue their lives but the gifts they have been given persisted and gave birth to new species across Akara. The Angels fought hard and bravely and a handful rose above the rest in their commitment to banish the demons. The Gods gave them the title of Valkyrie  tasked them with keeping an ever-present stand to protect the humans.
Of Course, the Daemonioum, though defeated, was not ready to give up. To this day they feed off the souls sent to the Agony grounds and search for new ways to crawl back into the material plane and gain control once again.