The Blood Flame Poison in Su Yu's body was placed there by his mother using hundreds of poisonous insects that grew around volcanic magma, carefully refined into a Gu Worm and then placed inside him from less than a month after his birth. It slowly sucked his blood and released toxins. As he grew, the Gu Worm's toxins gradually spread throughout his body. By the time the Gu Worm was extracted, his blood was already filled with toxins, forming this unique Blood Flame Poison.