1 Book Found

Based on your description:

"I remember the premise but I never finished the book, it felt like fever dream to read. Its about a group of kids who live in large kingdoms and ride dragons. Every generation the eldest children are called to the leading kingdom to battle each other to see which of their kingdoms gets the most power that year. There's a ceremony where what's supposed to happen and their dragons hear an invisible call of sorts. But instead, the second youngest get their dragons called instead, except for one who's a maid who had a secret lover's relationship with the princess. I think they kissed each other before the maid left Then there's this one scene where the youngest of the last kingdom is killed by her sister so she didn't have to face the other kids . I think she was only 12. Then her hyrda eats her peace by peace. There was a paragraph that described it as a being the most honorable way to die. The cover had I think 8 swords with gems and dragon symbols on it. And it was this deep purple color."