Time Flies and Is Filled with Sorrow

She has a noble status and is the eldest princess born from the mother of a country. But for him, she gave up her pride as a princess, just to give him a chance to live. He had an ill-fated fate and was the chief disciple of Old Man Xuanchen. But because of her, he was poisoned and endured bone-gnawing pain every month. In this world of mortals, what kind of life story will they interpret?