Asriel Dreemurr was the former prince of the Ebott Mountains, the son of Toriel and Asgore, and a kind, yet curious young goat. He was always so curious about the world around him and the magic that flows through it. This curiosity would lead the young prince to his disappearance. At the age of 12, he joined in an experiment in mixing Monster Magic and Determination together to bridge the gap between the two types of magic. The experiment turned into a complete disaster when the magic reacted violently to each other. As a result, Asriel's body was vaporized and his soul was sent to parts unknown. Some say that the young prince's soul was bonded to one of those Echo Flowers.

As a child, Asriel doesn't have a theme.