Huh. So her dad used something of Zenovia to prevent the eight disasters or w/e from roaming the land before he had his final fight with Dan? Sounds a bit funny, but plausible, if they're supposed to be overwhelmingly strong.
And also...I guess that means the cute fatty on the most recent volume's cover is whichever demon is supposed to represent "gluttony" on that group, with Via being "envy".