Disgaea

The Disgaea series is based on events from the game Disgaea: Hour of Darkness. Angel assassin Flonne is sent to kill the demon Overlord, but she inadvertently awakens Laharl, the demon lord and heir to the throne, from his two-year slumber. This leads to the formation of an unlikely trio, including Laharl, Flonne, and Etna, a demon vassal with an army of penguin-costumed minions. As Laharl attempts to restore order to the Netherworld, he must navigate power struggles and potential allies.