Nefretiri
I shouldn't have done this.
It was a huge mistake. Willow was five, but her power was almost as raw as an infant's. As long as she was docile, you didn't feel the effects head-on, but it changed when she actively gave me her energy. It healed me physically but didn't start there. Instead, going to my meridians and breaking the seals on the smaller ones before attacking the larger energy flow. That set a direct course for Kali, assaulting her form in the same way. Only, it was much more intense for her.
I always thought Kali was healthy, but again, I was wrong.