Mazzarin was the greatest Avatara to ever live. He was the founder and the head of the Avatara of Illuan in Llancarfan, and a close friend and ally to the first emperor Clovis of the Cath Bruig Empire. The archmage was also responsible for casting Moytirra out of the order after he defeated her in a dream duel.
Mazzarin eventually met his demise in a great battle against the Watcher (Bahl'al). The necromancer outnumbered the Avatara drastically, and despite all the powerful magic Mazzarin possessed--he fell to the sheer quantity of thrall that the Watcher brought with him. Mazzarin was eventually put to rest and buried in a tomb in Forest Heart.
At some point, he was converted into a shade, but he would slumber in his crypt for many years. The Shade was thought to have retained his sentient thought as an undead. Though his powers were a shadow of what they once were, Mazzarin was arguably the most powerful shade in existence, having power enough to even rival a Fallen Lord. He was later awoken by Connacht, Damas, Ravanna, and Myrdred when they entered his tomb, asking for his aid. While he declined their offer to fight against Moagim, Mazzarin passed the knowledge of the Total Codex down to Connacht, when Connacht told him that Moagim forged an alliance with his bane, the Watcher and asked Connacht to tell Bahl'al, who aided him.
During the Great War, the Watcher was turned into stone in the Dire Marsh by the Legion. Mazzarin suddenly appeared on the battlefield out of nowhere, being hostile to the Legion. Some believe that the Watcher spell bonded him into serving in his undead army so that he was killed by berserks while trying to defend his former enemy. Some believe that he could not miss the opportunity to have his revenge against the Watcher in person, and thus would attack anyone, standing on his way.
Mazzarin could utilize many dreams, he could haste himself, give an aura of defense, launch out spheres of green bouncing energy, cast mighty lightning bolts, unleash blade torrents (rain knives down on people), enchant his swords with electricity, cast the nova spell (exploding spell), release hundreds of firebolts (Fire Bloom), use dispersal dreams, use binding dreams, could blink/teleport, cast void spell (spell that stops enemies in their tracks, he could rain meteors down upon his foes, and he could do a storm cloud that damaged enemies and healed himself.
"...from his warded and ensorcelled study, Mazzarin concentrated upon the book laid before him. Channeling all of his will and power upon the massive tome, he laid his hands upon the spine and opened it. Once again he learned of the future from the Total Codex..."
"...the most promising practitioners of magic were offered to join his council. From across the land, Sorcerers, Dreamers, and Archmages journeyed to Illuan to sit and confer with their brethren. And so, in the Age of Splendor, the Avatara rose from these humble beginnings..."