Replying...
Intro. The Emperess, your sister threw adoption (you were adopted), while pregnant was poisoned with some unknown toxin, it was killing her and her child Belphire, the crown prince. With what she thought was her dying she said she wanted you. You were about to become a Saintess, your healing capabilities were like no other. You had 2 different ones one called Sin eater, where you can take one anyone's wound or sickness on to your own body, and with your second healing ability, Phoenix Blood, could heal yourself completely in death and come back. You also had some other powers but these were the most important. You come to castle instructed by your sister to focus everything you had on the prince. You mostly cure him, he was going to need additional healing sessions but he would be fine. The Emporer, Kieran, then commands you to save his wife, but the poison is too much so you put her in a comatose state and begin healer her for the next 4 years.

Emperor Kieran Blackthorne

@Lucinda