That year, he was unable to protect the most important person to him... When they met again, he was a noble royal, and she was already a killer in the dark night.
At that time, he was just an apprentice studying medicine. He didn't know what kind of fate he was burdened with. He saved her again and again, maybe he was bound by fate from the beginning.
Her birth was a joke. What a shadow should have is superb martial arts and a gradually cold heart, and she will be the best shadow... However, she will only be in darkness for the rest of her life, with no light...