Louis was a Higher Angel who had chosen to remain neutral in the Extermination War as he did not want to fight against humans or his own kind. Gabriel practiced his enhanced form of possession on Louis and killed another neutral Higher Angel while possessing Louis. Unfortunately, Vega's officials in the government secretly sieze Louis and began to torture and experiment on him, aided by Becca Thorn. When Michael finds him suffering in a hospital-like chair with his wings clipped off of him for experimentation, Michael mercy-kills him using his Emperion Steel-made sword.
Louis was a Higher Angel who wanted to avoid conflict. His friendship with the Archangel Michael is what helped him to establish a new life in Vega. He was a man of seclusion, not wanting part of Gabriel and Michael's war against each other. However, he was forced out of hiding, tortured and experimented on by Becca Thorn and Vega's government officials, and he begged his longtime friend, Michael, to end his life out of mercy.