Nozmodamus

Nozmodamus is the ruler of discror and one of the Daemon-lords/gods. he's the archenemy of the gatekeepers, and an enemy marceline the vampire queen, Finn and Jake, and the former ruler of the Night O'spere making him a rival of Hunson Abadeer.

he is the main antagonist of the Chaos Gate franchise.

History
Not much is known about Nozmodamus's past but we know that he is one of the offspring of the cosmic Dark Lord Nekrozoth. He was the first ruler of the night O'spere until Hunson dethrone him for some unknown circumstances. frustrated he went to earth to try to make it his new Night O'spere until he was defeated by a group of four wizards. they banished Nozmodamus and his horde of monsters to the realm called discror.

Chaos Gate
Nozmodamus went on working behind the scenes during the series as he watches Matt (the main character) across the series.

His followers called the servants of chaos (lead by Viggo) were trying to free Nozmodamus by finding the four keys to open the gate, the leader of the cult sent the Minotaur to find one of the keys. the Minotaur failed, so Nozmodamus grows impatient. So Nozmodamus punished Viggo by turning him into a reptilian hybrid.

Later on, in the series, the cult finally succeed in finding all the keys. the gate finally opens and  Nozmodamus was free. he taunts Matt and the gatekeepers while shooting fireballs at them. Matt uses his power of electricity back at him but to no avail, but he remembers that he can mimic others power so he copies Nozmodamus's attack and uses the divine flame to defeat him. Nozmodamus was defeated and was reimprisoned once again.

Personality
He is cruel, ruthless, arrogant, and an egotistical demon who enjoys bringing bad luck to others for his own amusement. Nozmodamus is also Cunning, selfish and manipulative.

Despite being a cold-blooded warlord, he shows to be loyal to his master Nekrozoth, but unlike Nekrozoth he does sometimes keep his end of a bargain when he makes a deal (if he wants to). despite being a daemon-lord he is one of the inferior ones due to him being the third youngest one and not being a god.

Though inferior he is quite intelligent, being intelligent enough to easily break from his prison and make a vast legion of followers. he can get impatient and doesn't tolerate failure if his minion fails him he gives them severe punishment or transform them into vicious creatures.

besides Matt, the person he hated the most is Hunson Abadeer. Because of Hunson dethroning him, he plots to get revenge on him even if it means he has to kill his family to do so (like he did to Hunson's wife and tries to hurt marceline too) he calls Hunson "Inferior to take the throne" or " a disgrace to demonkind" due Hunson soft side to Marceline and her friends, thinking he is a "weak pathetic idiotic soft demon who thinks himself to be the devil". He is still inferior to the rest of the Daemon-lords but he is still intelligent and loyal to Nekrozoth