Dahlia and Esther's Family Bloodline

Dahlia and Esther's Family is an ancient bloodline of very powerful Nordic witches that goes back at least a thousand years, and is notable for boasting not one but two witches who have been stated to be among the "most powerful in history". 
This bloodline's known witches have all been powerful and noteworthy. The family's known oldest and currently most powerful known ancestor is Dahlia. It is revealed by Dahlia that this bloodline's first born inherit incredible power which is so strong, it can destroy both the witch and its surroundings. The family's many achievements include creating more than one form of immortality and various other powerful magical spells.