Disclaimer: I do not own any of the anime and/or game characters from the anime and the game they come from. They all belong to their original owners.
Prologue: The Legacy
Our world was peaceful as long as anyone can remember. Our land was beautiful with lush green forests, mountains that looked like they could touch the sky, oceans with water so clear, you could see the creatures living out their own lives. Best of all was the people living in our land. They were happy with their lives and were happy with the person they loved the most. Different races existed within our world and each had a complete understanding of the other's culture. All of this was being watched by our benevolent queen. Although a bit dim time to time, she always tried her best to please her people. She had such strong friendships with the neighboring kingdoms as well. Yes everyone was happy, that is until that day.
One night when the moon was full, a dark circle emerged and covered the moon with a sense of an evil light coming out of it. A violet earthquake shook the land and a large crevasse began to form. From that crevasse, a large gothic castle emerged. Soon dark clouds with red lighting began to appear all around it. It was soon learned that the one who lives in the castle was the demon queen, Rias Gremory. She sent her forces out onto the land to conquer the land while abducting the women so they could be part of her harem. Of course our queen retaliated to the attack but we soon learned how powerful the demon queen's forces are. Our armies' were either killed or captured to be either part of her army or her growing harem.
Hope was rapidly declining in our land. Now even mentioning the name "Rias Gremory" installs fear in the people. The people mourn their loved ones who were taken away from the demon queen. They could only imagine what they were going through in that castle. Some say as soon as the women join the demon queen's harem, they lose all memory and only have love and lust for their queen. As of now, our queen is doing her best to fight off Rias' armies but it was slowly turning into a losing battle. Then a queen from the kingdom of elves requested an audience with our queen.
She said she may have the answer to end this terrible war. The elves were skilled in magic and healing but a long time ago they developed a kind of summoning magic. Along with this, the elf queen saw a prophecy. If ever the dark forces arise from the earth, seven warriors shall be summoned from different worlds. They are last line of defense to battle the forces of darkness. Just hearing this made our queen hopeful once again. She didn't know if this would work or not but it was better than nothing. Now in this desperate time, one last hope still exists. This is the battle between good and evil. A battle of fate itself.