Makai Senki Disgaea

Angel assassin-in-training Flonne arrives in Hell, intent on destroying the demon Overlord. However, her mission is derailed when she inadvertently awakens Laharl, the demon lord and heir to the throne, from his two-year slumber. Joined by Laharl's not-so-faithful vassal Etna and her army of penguin-suited explosive souls, the unlikely trio sets out to restore order to the crumbling Netherworld. As Laharl seeks to reclaim the throne and quash the demon rebellion, he will stop at nothing to destroy anyone who stands in his way - unless, of course, they choose to join him on his travels.