|Sources||Guildpact, Dissension, Return to Ravnica|
Niv-Mizzet is the draconic leader and parun of the Izzet League and is at least 15,000 years old. His intellect exceeds the intellect of standard mortals by several echelons, and he is known for many ingenious inventions that currently serve the citizens of Ravnica, the most well known being the almost indestructible, yet easily usable and forgeable metal, mizzium. 
As time wore on, he became further and further reclusive and wasn't seen publicly for over 2500 years prior to his appearance to help the goblin master engineer Crixizix deal with the rampant nephilim. He destroyed two of them, but fled after being injured by an unforseen attack by the nephilim, who had been empowered by consuming the flesh of a dragon. He left the battle, claiming that he was bored of the fight, for an unknown destination in the northern aeries and did not return whilst the Nephilim ran amok.
His disappearance from Ravnica seemed to be complete, as even those who were tied to the Firemind could not find him. However, he later returned as a signatory for the new guildpact negotiated by Teysa Karlov.
The Firemind is an extrasensory link to Niv-Mizzet’s omniscience. To possess it is to be immersed in passionate brilliance. Not all Izzet are in tune with the Firemind though; the honor must be earned by passing a test or by accomplishing an extraordinary achievement.
The Implicit Maze
Long after the Guildpact had been laid to waste the Izzet League undertook a masive research project that spanned the 10th district. Niv-Mizzet put many of his guild's most powerful mages, including Ral Zarek, into a scavenger hunt across and under the city in search for the secrets of the Implicit Maze. This project was progressing slowly until Jace Beleren used his powers to peer into the dragon's mind to learn the secrets that Niv-Mizzet sought. Fascinated by the mindmage Niv-Mizzet took Ral Zarek out of the Maze project to discover what Jace had learned. Partially successful in this Zarek was sent to deliver an invitation to the other guilds, urging them to send Mazerunners to the Transguild Promenade. Niv-Mizzet went to work creating the Izzet Mazerunner, a Weird made from Ice and Lightning that he called Melek. At the Transguild Promenade however a disgruntled Zarek destroyed Melek and replaced him as the Izzet Mazerunner. Niv-Mizzet arrived at the Forum of Azor shortly after Jace Beleren used mindmagic to halt the aggression between the Runners and after a tense stand off with Jace he lef to ponder the Guildpact's return.
- His card's flavor text "(Z->)90° - (E-N²W)90°t=1" is very well known, and has led to multiple interpretations; one such is that it reads "Niv-Mizzet = 1", as when one turns the symbols in the parenthesis 90 degrees, it reads "(NIV)-(MIZZE)t=1", a possible allusion that he considers himself #1 in every aspect, or that he is the only higher dragon left in Ravnica. Mark Rosewater's comment on the "=1" part was that this means "equal 1 copy of his name". Another interpretation is that his ability to tap to draw a card does 1 point of damage.
- It has been confirmed that Niv-Mizzet doesn't leave Ravnica, defusing speculation that he could somehow planeswalk. 
Quoted or referred to:
- Crackling Perimeter
- Enter the Infinite
- Hypersonic Dragon
- Invoke the Firemind
- Izzet Guildgate (Dragon's Maze)
- Izzet Signet
- Nivix, Aerie of the Firemind
- Skinbrand Goblin
- Warmind Infantry
- Matt Cavotta. (January 11, 2006.) "Niv-Mizzet, the Fountainhead", Daily MTG, magicthegathering.com, Wizards of the Coast.
- Mark Rosewater. (December 10, 2007.) "What Do You Know, Part II", Daily MTG, magicthegathering.com, Wizards of the Coast.
- Brady Dommermuth. (January 30, 2009.) He remains on Ravnica. I will say no more.