The character known as "Lukia" corresponds to the demon Luka (alternatively spelled Lukia) from "The Testament of Sister New Devil BURST". A male demon researcher aligned with the Demon Lord Faction, Luka serves as a top magician under Demon Lord Leohart, defined by his unwavering loyalty. He possesses an "adorable-looking young man" appearance, featuring facial markings beneath his eyes and demonic horns. His primary focus is researching and upgrading ancient relics to adapt historical magic for modern use. In combat, he summons and controls Heroic Spirits. Following defeat by Mio Naruse during factional conflict at Rendval, Luka declines a position on the new demon council, choosing instead to return to an academy to concentrate on his research. His goal is to enhance Heroic Spirit technology to eventually support Leohart on the frontlines. Luka exhibits a workaholic nature, often working to exhaustion unless expressly ordered to rest by Leohart. His loyalty to Leohart is absolute, adhering to the principle "my master, right or wrong." During a tournament, he summons a Heroic Spirit against Mio but expresses no personal animosity, stating "don’t think badly of me." His character development centers on dedication to scholarly pursuits as his means to contribute to Leohart's cause after stepping back from direct combat.