Lyrae was originally a higher angel who punished wicked humans. Michael punished him for breaking the law of God by expelling his spirit from his body, making him a lower angel. He later combined spirits with an unknown human, making him a Dyad, becoming Julian.
Lyrae was extremely loyal to Michael and Gabriel during The Great Flood. He can also be seen as animalistic because he took joy in killing humans, unlike Michael. Michael only wanted to cleanse the Earth of sin. However, Lyrae was obsessed with the cause and obsessed with pleasing Gabriel and Michael. This loyalty ultimately cost his life and higher angel-status.