Desco

Desco is the prototype of DES X, and a man-made demon created by humans to be the ultimate weapon. She was abandoned in Hades for being defeated by DES X. Because of her destructive potential, she was sealed in order to contain her power, but Axel, thinking she would do his bidding, releases the seal and unleashes the "terrifying monster". In order to show off how Final Boss-like she is, she seemingly vaporizes Axel, and then proceeded to fight Valvatorez, Fenrich, and Fuka, who had recently joined the main party. Upon her defeat, she thought she was going to be abandoned again for losing to a band of "heroes" who weren't really heroes, and began to cry. Shocked by this revelation, and by the fact that she was an artificial demon created by human hands, Valvatorez declares that he will re-educate the demons and humans for their foolishness. Valvatorez decides to take Desco along with his party, especially after Desco reveals that Fuka is her "Big Sis", much to Fuka's surprise. She calls Fuka "Big Sis", because she was artificially created by Fuka's father for Fuka who wanted a little sister with advanced functionality who could help her take over the world.