Empra, known as Koutei Ani (こうていあに, Kouteiani, lit. "Elder Emperor") in Japan, is a demon in the series.
DemiKids: Light & Dark Version
Empra appears in both Demikids Light Version and Demikids Dark Version, but only speaks and is fought in Dark Version by Akira and Gale. He rules Valhalla and has created severe unrest among the demon world. In his quest he has destabilized time, causing the time rifts shown all over the game. His goal throughout the game is to conquer the realm of Dem and Lucifer, control Valhalla, and the time tower, then spread into the human world until he controls it all.
Empra is only called Imperius throughout the game, and no time during the game does he ever speak to Empio or mention his name being Empra, his name only appears in text boxes as Imperius. At one point he captures Lena, and brings her to his castle before anyone can rescue her. She meets her death when she pegs Empra for a coward, which he does not rebuff, he then executes Amy later in the game.
At the end of the game, Jin and Akira decide to fight the twin Imperius lords. Jin takes Empio while Akira takes Empra. After the battle, Jin chases Empio into a dark void and is not seen again until the ending, while Akira chases Empra into the light void, and faces Empra again when he fuses to Seipher. Seipher and Empra both explode, and the reign of Imperius ends.
Since both games are canon to the Devil Children games, it is implied that while Empio does not talk while Empra does all the talking, Empio and Empra are both speaking.
Devil Children: Light & Dark
DemiKids: Light & Dark