Boyle was born into a poor family, he witnessed his family die at the hands of Demons. He joined the Divine Empire as soon as possible to get revenge. Driven by rage, he became an excellent Demon Hunter, but his low social status eclipsed his great achievements in war. 

    He was only given command of the Guardians of the World Tree. Tricked by Dora, Doyle led a team of Orcs and destroyed the roots of the World Tree, freeing the Prime Evils. Doyle disappeared after that and became the Night Sentinel, seeking revenge at all cost, burrying his feelings deep down.