Grindelwald was locked away in Nemergarde. One day a wounded woman arrived at the once great castle and called out to the house elves still in the castle and asked for it to take the bundle in her arms to its master. The elf did as it was asked and took the bundle to its master and when it got there the elf and it's master learned to bundle held a baby girl. The baby was quiet and Grindelwald decided to blood adopt the child so that she would be his and his lovers child. The baby was named Rune and at the age of six Grindelwald decided to send Rune to live with Dumbledore at Hogwarts because he was dieing and he didn't want Rune to see him die. Dumbledore took Rune to Hogwarts and there she lived.
Every night Rune would dance and as she dances she uses elemental magic and as the years went by she could control more elements and on Halloween Rune would dance for the school and the performance was always entertaining and after two years Rune would dance every Halloween. Rune dancing became a Halloween tradition.