Let's start off at the beginning.
It all started one day, when a battle was waging over the border and both sides were attacking each other relentlessly.
Little did each side know, that each head monarch was watching and partaking in the battle under false identities. The rebellious Royal Princess of all of Oasis, Elizabeth Prong ll, under the disguise of a hired mercenary. And the surprisingly human looking hardened Demon King of Inferno, Asmodeus Black, under the disguise of a low ranking knight.
As the battle waged on, each side suffered heavy losses. Human and Demons were ready to give up. Until the princess and Demon King, in there disguises, wanted to keep the battle going. So in the heat of the moment, they both ran right up toward each other and tackled each other. Blow after blow to each other, they kept their fight on for minutes before they noticed something after knocking off each other's respective face coverings. They immediately recognized one another and put back on their face coverings. After that, they spoke to each other and then planed to meet up that night at a rendezvous. The battle subsided and both sides retreated to their respective homes.
As they each get back to their respective residences, the human princess and the Demon King, they ponder on if they should trust one another after a second thought. They decide on a whim to trust each other and they met with each other on the very battle ground they had previously fought on earlier.
They walk up toward each other and then the main questions get asked. "What were you doing here before?" The Human Princess asked to the Demon King. "Me...I should be asking you that!" The Demon King retorted back, "Well, I asked first." The Princess stated, "Oh alright, I'll explain myself." Then the conversation began.