After being killed by the Hero's party, the main character was reincarnated as a weak baby goblin inside the alien dungeon/tower called the Roots of Akasha. From here, he must face different kinds of creatures from different origins... aliens, zombies, hostile AI, demons and gods.

Can he fight all of them? No... So what must he do to survive? Deceive them, manipulate them, use them, assassinate them, and be the king of all these monsters.

This is the story of Aku, and how he became the generations most feared Dark Lord.