Basic vampire abilities
Heidi was born in the 1520's in Germany. She was very beautiful, happy, adoring, and kind to others, allowing men to come after her. Heidi was wise to avoid them, but the only thing she liked was spending time with children. She always took care, and loved children as her playthings when she grew up as a maid. After the death of her parents, Heidi took her responsibility of taking care of her baby brother. Heidi always watched her brother and never let him go. She would take him somewhere around the country, exploring the wilderness around when the sun is bright, and enjoy a peaceful life. Everything changed after that.
After Heidi turned 26, she met a young woman named Hilda who was revealed to be a vampire. Hilda saw how beautiful she was, and she decided to offer her a gift of immortality. Heidi accepted her offer, and promised to look after her brother and protect him from harm. She was turned into a vampire, but after her transformation, she nearly killed her little brother when he hurt himself. Heidi was able to resist the thirst, knowing that she couldn't hurt her brother. Heidi feared that if she stayed close with her brother, she would get his life in danger by vampires, so it was time to let him go. Her brother was taken care by a peaceful foster family, and wished her brother goodbye. Heidi knew that she would never see him again, and this was the only part that she had to do.
Spending more than a century with the coven of vampires, Heidi started to get use with her mates, and spend time hunting Humans. Heidi chose to feed on the elderly instead of the young since she suffered memories when she nearly killed her brother and how she truly loved children.
This was when the Volturi accused Hilda and her coven for treason. Hilda begged Aro to spare her coven mates and allow herself to die for the guilt she did. With Hilda's death, Heidi was upset, and decided to leave until Aro was intrigued of of her gift. He decided to keep her as one of the guards while he allowed the rest of the coven mates to leave and run into hiding from the Volturi. Heidi became bound to the Volturi and betrayed her coven mates. Her main responsibility in the Volturi is arranging elaborate ploys to bring elderly human victims that are in their 60s, 70s, or 80s to Volterra.
After the second confrontation between the Volturi and the British Coven, Heidi fled from Volterra, knowing that she was free from Chelsea's power. She moved to England where she offered her service to Gabriel. It took a while for Heidi to get use to drinking animal and human blood at the same time.