Ka Na/History and Plot

==Light Novels==
Ka Na once met with the Yellow Immortal and questioned him on saving a human's life. He becomes a physician so he could find an answer to her question. Along the way, he discovered and developed human surgery. He taught this to her and later granted her the gift of healing as well as teaching her many things about the practices of medicine.
While she was under the tutelage of the Yellow Immortal, Ka Na wrote many books concerning diseases, remedies and cures. These were then passed down to her descendants (who added their own findings to the collection) and are considered invaluable by those in the field of medicine.
When members of the court saw Ka Na put a knife near the Emperor, she was suspected of having tried to kill him and was executed. But the Emperor was ill and what she was really trying to do was operate on him.