Aku
A truly legendary figure in The Monsters taxonomy, Aku has been called by many names across cultures and through time, most famously “The Shape-shifting Master of Darkness.” We are remiss to call Aku's disposition evil but they are certainly not shy of chaos. Though particularly social and incredibly receptive to praise, Aku seems to draw great personal satisfaction from inciting discord amongst The Monsters.
After initial contact we were blown away to discover Aku not to be a Monster at all but an entire subspecies known colloquially as The Demons. While instigatory when in the company of The Monsters, The Demons seem distinctly placid in the presence of one another. It is our current theory that The Demons are a divergent relative whose development specialized along the essential dark aspect in their nature of these esoteric creatures and, to a lesser degree, The Monsters as a whole.