I played in these games: "Overlord", "Overlord:Raising Hell", "Overlord II". In first game I really liked to play the Overlord and his minions. But after "Raising Hell" he was locked in Hell. And his son become the New Overlord. "Overlord II" was very funny. I like that. But the New Overlord wasn't the Old one. I really liked these really good high man, who atacked Hell, had battle with the Forgotten God, but was locked. As Gnarl said in the end I liked Overlord (I know, he said another word, but the meanings are same).
So, please, return him from hell in "Overlord 3" or in "Overlord 2 Addon" or anything else.