D&D: The Planes' Conqueror

A Warlock by the name of Ivanhoff had been banished to the lowest level of the Abyss due to his powers and his attempt to become the God of Destruction, his allies scattered... but somehow Ivanhoff returned and now he has more power than before and is building an army capable to take the Planes by force... luckily the youngest of the original heroes who banished him still lives... find him and take down this rising threat before it's too late...