Morjec is a Human wizard of great power and subtlety...or at least he is now. He is recognized as the power behind the throne of Arin, as he has been for some fifty years.
Little is known of Morjec's early life, although he is said to have been born in southern Arin. His magical abilities were evident early on, and he was chosen by Keraptis, then the de facto ruler of the land, to become his apprentice.
The Onyx Empire
As the center of the Onyx Empire, Arin was Keraptis' base of operations, and as his right-hand man Morjec was responsible for its military operations. His specialty was luring high-level military commanders and adventurers into traps of his own devising, usually involving dungeons that were scattered throughout Lanad i'Sarois. One of his trademarks was to hide such dungeons by illusion, leaving only the door visible to be found by the curious and unwary, including one located in Seldann Wood itself. It is rumored that some of these traps still lurk in the UnderWorld, waiting to be sprung.
The Wars of Arin
During the Wars of Arin, Morjec commanded the southern forces of Keraptis' army. His forces were able to push deep into Kellan before being stopped at the Battle of Hanmer. This allowed the White Alliance forces time to regroup and eventually outflank Morjec's forces, cutting him off from support. He was able to flee, but this would be the undoing of the Empire and of Keraptis.
The power vacuum
When the empire fell, Morjec did his best to put the pieces back together. He started out trying to continue the Wars of Arin, staging an attack against Braith. He even went so far as to hire the noted assassin Slug to kill Thorin Archer. He later sent one of his servants, Jerome, to infiltrate the White Army in Semmarch and undermine the defenses there, although that plan was foiled by Beatrice and her company.
This series of defeats led Morjec to change his tactics. He recruited Sargon, an arrikhan who has been called The Black Knight, to be his mouthpiece to the world, while he withdrew to carry out his plans in secret. He supported the return to power of the former royal family of Arin, now led by King Lloyd IX. Of course, as the royal vizier to the king, he has positioned himself as the real power in Arin. While the citizens of Arin are preoccupied with the rebuilding of Arin's capital, Arek, Morjec has rebuilt his army of orcs, grazhnakh, and other horrid creatures, preparing for the time when he might again challenge his neighbors in war.
Over the years, there have been many rumors about Morjec, including that he has close dealings with high-ranking baatezu, or even that he himself is half-devil (or even a full-blooded fiend!); that he is actually a clone of his master, Keraptis; that he has forged alliances with other evil wizards to mutual benefit; and that he is somehow connected to the withdrawal of Hanaellan from the White Alliance. How much of this is true is likely known only to Morjec himself. Whatever else might be said of him, his intelligence should not be underrated.