Dugu Xin was born on the day his mother died, from the combined stress of childbirth and prolonged exposure to her husband's poisonous body. He was raised by his father, and trained harshly his entire life to counteract the terrible side effects of their family's signature spirit, the Jade Phosphor Serpent. Despite his training, and the help of his increasingly powerful father, Dugu Xin spent much of his life in terrible pain. By the age of 15, all five of his major organs had been infested with poison, but he was able to survive to the age of 35 thanks to his father's obsessive love and care. He died on the very day Dugu Bo attained Rank 90, the threshold that would have allowed him to save his son's life.