Hecate

I came up with an idea for puff's lore! I have to retcon a couple things though. She knows her name as pinkie but originally she was named Hecate. Pinkie never leaves her lake, because she is the spirit of the lake itself. Every couple centuries or so she begins a "new life" by being frozen in her lake. She forgets all her prior memories. By preventing North preventing this, she was able to remember him.
She lives on the border between the starfall isles (arcane) and Southern Icefield (ice), both of these magic keep her alive. This is why she survives extreme conditions, why she can take energy from the land to use, why the land seems to protect her (like covering her with flowers in the cold) as she is apart of the land. This is also why she rarely leaves her lake as she is tethered to it.
Years ago, her parents gave Hecate to the lake as she never hatched from her egg. The land felt the grief of her parents and had mercy on them, giving Hecate a new life. Her parents were with her for her first life, and when they died Hecate was reborn. She has been given many names, lived many lives, but she doesn't remember them.